INFORMATION FORESTRYPacific Forestry Centre

Victoria, British Columbia

December 1997

ISSN 0706-9413

Natural Resources Ressources naturellesCanada Canada

Canadian Forest Service canadienService des forêts

DDwwaarrff mmiissttlleettooee((SSeeee ssttoorryy oonn ppaaggee 22))

Inside...Managing Dwarf Mistletoe. . . . . . . . . . . . 2

Catching Tree Thieves . . . . . . . . . . . . . . 3

Getting to Know Yew. . . . . . . . . . . . . . . . 4

Detecting Forest Pests . . . . . . . . . . . . . . 5

Is There Life After Old-Growth? . . . . . 6/7

Studying the World Underfoot . . . . . . . . 8

Laminated Root Rot Resistance Research. . . . . . . . . . . . . . . . 9

Light on Canopies . . . . . . . . . . . . . . . . . 10

Staff Comings and Goings . . . . . . . . . . 11

Recent Publications . . . . . . . . . . . . . . . 11

Upcoming Events . . . . . . . . . . . . . . . . . 12

“Research

into

devel-

oping a biological

control strategy for

dwarf mistletoe

looks promising...”

Dwarf mistletoe may sound like a cutefestive ornament, but in a forest it canmean disaster.

Not to be confused with Christmas mistle-toe (Viscum album), dwarf mistletoe(Arceuthobium spp.) is a parasitic plant thatinfects conifers, causing suppressed growth,decreased wood quality and reduced seedcrop production. Found in western Canadaand the U.S. as well as parts of Mexico andAsia, dwarf mistletoe causes more damage tocommercially important conifer timber standsthan any other pathogen, with annual volumelosses estimated to be over 3.7 million m3 inB.C. alone. The Canadian Forest Service isdeveloping a biological control strategy tomanage the parasitic plant.

“Although research studies into biologicalcontrol of dwarf mistletoes took place in thelate 1960s and early 1970s, it did not continuebecause logging practices at that time reducedthe impact of dwarf mistletoe infection,” saysDr. Simon Shamoun, research scientist in thePest Management Methods and Effects ofForestry Practices Networks. “But the currentemphasis on partial cutting means that it istheoretically possible that every tree plantedor naturally regenerated will be literally show-ered with mistletoe seeds (inoculum) frominfected border trees, resulting in plantationfailure. Biological control strategies would beparticularly appropriate in respect to currentforestry practices where direct silviculturalmeasures are not possible.”

Adds Dr. Paul Addison, manager of theEffects of Forestry Practices Network, “Dwarfmistletoe can limit the use of partial cutting(non-clearcut) systems in many places inCanada. An effective biological control strate-gy for this species will be one more steptoward sustainable forest management.”

So far, Shamoun’s research into develop-ing a biological control strategy for dwarfmistletoe looks promising for two of B.C.’smajor conifers, western hemlock and lodge-pole pine. Working at the Pacific ForestryCentre, he has identified two hyperparasiticfungi that are potential biocontrol agents. Oneis Colletotrichum gleosporioides, a speciesthat attacks the shoots and berries on westernhemlock and lodgepole pine dwarf mistletoes.The other, Nectria neomacrospora, destroys

the endophytic system (the internal swelledareas on an infected tree branch) of westernhemlock dwarf mistletoe, preventing the re-sprouting of mistletoe shoots.

“Our plan is to develop a multiple infec-tion formulation where both the shoots ofdwarf mistletoe and its endophytic system areattacked by fungi that are not only indigenousto B.C. but are specific to certain organs in theparasite,” explains Shamoun. “Such a biocon-trol strategy does not upset the ecosystem byeradicating the parasitic plant completely, buteffectively manages dwarf mistletoe by reduc-ing the amount of inoculum.”

Shamoun plans to treat infected trees bor-dering new openings in partial cut stands, orsingle residual trees within openings, ratherthan treating entire stands. “It has beenobserved (in openings) that as the crown oftrees expand, the mistletoe plants in the interi-or of the crown eventually die out, and if therate of growth of the trees sufficiently exceedsthe spread characteristics of the mistletoe, thetree can escape infection. An effective biocon-trol agent therefore does not have to eradicatemistletoe from entire stands.”

In keeping with the concept of managingdwarf mistletoe without disturbing the com-plexities of the ecosystem, Shamoun alsoplans to investigate genetic resistance strate-gies that are both environmentally acceptableand economically feasible.

This research is being conducted in coop-eration with: Forest Renewal B.C.; the B.C.Science Council; the B.C. Ministry of Forests(Vancouver and Kamloops regions); industrialpartners MacMillian Bloedel, RiversideForests Products, Dr. H. Kope (Contact Biologi-cals Inc.), and Dr. W. Hintz (MycoLogic Inc. -University of Victoria); graduate students S.Deeks (c/o Dr. Z. K. Punja, Simon Fraser Uni-versity), T. Ramsfield (c/o Dr. B. Vander KampUniversity of British Columbia) and C. Jerome(c/o Dr. B. Ford, University of Manitoba); andC. Oleskevich, Dr. A. Thomson and Dr. R.Hunt of the Canadian Forest Service. Currentlycollaboration is underway with U.S. ForestService in Alaska, Washington and Oregon.

Dr. Shamoun can be reached atsshamoun@pfc.cfs.nrcan.gc.ca

Pest Management and Effects of Forestry Practices Networks

2

Managing Dwarf Mistletoe - A Biologicaland Genetic Control Approach

3

Catching Tree Thievesusing DNA Analysis

of Forests. “Not only will DNA help catchthieves, it will also deter them.”

Due to the complexity of this initiative,the first phase was limited to DNA matchingin yellow cedar only. “But since the researchwas so successful with yellow cedar,” addsWhite, working at the Pacific Forestry Centre,“we applied it to red cedar, some of whichwas 257 years old. That was a bit more chal-lenging as at that age the heartwood is full ofcontaminants which kill the enzymes used toanalyze DNA. But we found that extracting theDNA from a block of an old tree was possible,which means that this forensic technique maybe applied to forest products like cedar shakeswell after the tree has been stolen and thewood processed.”

Although similar DNA analysis tech-niques have been used to analyze forest genet-ic diversity, DNA matching in trees has neverbefore been applied to forensic purposes inCanada. But should the research prove to besuccessful in apprehending thieves and deter-ring them from stealing, it is possible that theprocess will be applied to other tree speciesacross the country.

Dr. White can be reached atewhite@pfc.cfs.nrcan.gc.ca

Their getaway vehicle may be a loggingtruck rather than a white Ford Bronco,but tree rustlers might soon be subject to

forensic techniques similar to those used toapprehend other criminals. DNA analysis maybecome a vital investigation method for appre-hending tree thieves and ultimately curbingthe crime.

The Canadian Forest Service in partner-ship with the B.C. Ministry of Forests has beentesting the feasibility of tree genotyping (usingDNA to distinguish between individual trees)to determine if a specific log has been harvest-ed without authority.

“The results from the feasibility studyhave been very encouraging,” explains Dr.Eleanor White, research scientist with theCanadian Forest Service, Forest BiodiversityNetwork. “We were able to extract DNA fromneedles as well as from the inner bark of yel-low cedar. We cloned the DNA and screenedthe genomic clones for microsatellites (highlyvariable DNA regions used as DNA markers) tosee if enough of them could be identified forindividual genotyping. Not only were we ableto extract the DNA in large amounts and main-tain good quality, but we discovered that thegenome (all the genetic material in the chro-mosomes) of yellow cedar contains the geneticstructure that would be necessary to do DNAmatching.”

Tree thefts occur on Crown land, privateland, and on ecological reserves throughoutCanada’s forests. In B.C., between 10 and 20million dollars annually is lost to tree rustlers.Convictions in the past have been securedthrough matching the shape and annular ringsof a “biscuit” piece cut from the butt of thestolen tree with its stump. But thieves nowremove a meter from the butt of the stolen logto make the “biscuit” technique ineffective.Without that technique, “catching them in theact” is virtually the only evidence that canstand up in court against an accused individ-ual or company. Through DNA analysis, how-ever, a tree thief could be convicted even ifthere were no witnesses to the crime.

“The goal of this project is to provide‘baseline DNA data’ to make the matching ofDNA in individual trees much easier and lessexpensive,” says Jerry Hunter of the Compli-ance and Enforcement Branch in the Ministry

“DNA

matching in trees

has never before

been applied to

forensic purposes in

Canada.”

Dr. White (centre) with assistants in the DNA lab

Forest Biodiversity Network

The most exciting phrase to hear in sci-ence, the one that heralds the most dis-coveries, is not ‘Eureka!’ (I found it!) but

‘That’s funny’... Isaac Asimov

When it comes to research on Pacific yew,“That’s funny” is a common phrase. Since thediscovery of Taxol, an anti-cancer drugextracted from the bark of Pacific yew,researchers at the Pacific Forestry Centre havebeen studying the distribution, growth andresiliency of the species to determine its toler-ance to environmental stresses. The resultshave been very surprising.

“Before 1991,” says Dr.Al Mitchell, Canadian For-est Service research scien-tist in the Forest Ecosys-tem Processes and Effectsof Forestry Practices Net-works, “you could askresearchers questionsabout Pacific yew —Does it grow in openareas? Can it growquickly? Does it survivein water deficientareas? Would vegeta-tive propagation of oldtrees in natural standsbe possible? — andthe answers wouldhave been no. Butresearch now indi-cates that theanswer to all ofthese questions isactually yes.”

Pacific yew isa long-lived treeusually found in

the understory of old-growthstands. This led to the assumption that the treeis slow-growing and intolerant of full sunlight.However, studies on acclimation to sun andshade now indicate that Pacific yew has manymechanisms to mitigate stresses associatedwith growing in exposed areas.

Although Pacific yew grows slowly in thedeep shade of natural stands, intensive nurs-ery culture of rooted cuttings of Pacific yewcan result in substantial growth (40 cm year-ly). This may mean that yew grows slowlybecause of the low light environment and not

4

Getting to Know Yewnecessarily because it is genetically pro-grammed to grow slowly.

“It was also believed that Pacific yewcould grow only in riparian zones (nearstreams),” explains Mitchell. “But throughmonitoring soil water deficits and photosyn-thesis, we found that Pacific yew can toleratesevere water stress. It appears that althoughtrees growing in different areas may lookremarkably different, they seem to be able toacclimate to a wide range of environmentalconditions.”

With respect to the likelihood of success-ful vegetative propagation (rooting cuttings),Mitchell explains that because Pacific yewtrees in natural stands tend to be very old (100to 300 years) it was assumed that they couldnot be propagated (it is almost impossible topropagate pine trees over the age of 60). ButPacific yew can be successfully propagated,even if the tree is well over 100 (althougholder trees were harder to propagate).

One of the most surprising discoveries inPacific yew research has been the detection ofthe yew big bud mite. “During our investiga-tions of Pacific yew stress tolerance, we madea serendipitous discovery,” said Mitchell.“There is a mite that infests the buds of Pacificyew (Forest Pest Leaflet 79, May 1997) and wehave deduced that it may have been intro-duced to B.C. from Europe. This mite couldaffect the success of programs to conservePacific yew through cultivation in nurseries.”

The Pacific yew story has been a voyage ofinquiry and a demonstration of how the searchfor conservation and cultivation options forthe sustainable development of Taxol has ledCFS researchers to discoveries that will helpto predict and prepare for the consequences ofdisturbances to Pacific yew and to forestecosystems.

Adds Dr. Paul Addison, Manager of theEffects of Forestry Practices Network, “Thebasic understanding of this species is funda-mental to the development of strategies for itsmanagement. In this case, Dr. Mitchell hasagain demonstrated the need for research inforestry.”

Dr. Mitchell can be reached atamitchell@pfc.nrcan.gc.ca

“T he

Pacific

yew

story has been a

voyage of inquiry.”

Pacific Yew tree

Forest Ecosystem Processes and Effects of Forestry Practices Networks

For some, the word “exotic” triggersthoughts of tropical islands. But for Cana-dian Forest Service (CFS) scientists Dr.

Lee Humble and Dr. Eric Allen, “exotic” cou-pled with the word “species” may mean seri-ous damage to native plants and trees, as wellas to native insect species in Canada.

Pests or non-indigenous species fromother countries have been “hitching” rides oncargo or dunnage on ships since the beginningof trade on this planet. Although few speciesoutlast the journey, survival rates are rising asvessels coming from other continents now takeless time to arrive at our ports. Greater num-bers of containers being shipped across bor-ders, more trade from temperate countries, andchanges in the overall global movement ofpeople all raise the potential for exotic speciessuch as insects, fungi, nematodes, bacteria andplants to reach our shores. In collaboration

with the Canadian FoodInspection Agency, CFSresearchers in the Forest Bio-diversity and Forest HealthNetworks attempt to deter-mine what native and non-native species are presentwithin Canada’s borders.

“We often don’t knowabout these pests untilsome time after they’vereached our shores,” saysDr. Allen, head of the For-est Health unit at thePacific Forestry Centre.To determine the path-ways through which

exotic pests enter the country, Dr.Allen focusses on quantifying high-risk com-modities such as wood-based wire rope spoolsthat have been found to contain some non-native insects. In cooperation with other scien-tists in the Forest Health Network, he is devel-oping detection methodologies and creatingrisk scenarios to determine the likelihood ofcertain non-indigenous species establishing inCanada. Taking into consideration the life his-tory of a particular species, Dr. Allen looks atthe climate of the country that the species isnative to and matches it to where the climatemay be similar in Canada.

“Three years ago we started looking atsome urban parks and national wildlife areasin B.C.’s lower mainland to see if certain non-

indigenous species that were a threat toforestry were established,” says Dr. Humble,an entomologist who heads two insect trap-ping projects in the area. Two exotic speciesthat the research team were trying to locate,the European spruce bark beetle and the Euro-pean pine shoot beetle, were never found.However, Dr. Humble and his staff did discov-er four well established exotic European orAsian ambrosia beetles.

From these forested areas on the lowermainland, 1500 trap collections were broughtback to the insectary at the Pacific ForestryCentre for inspection this past summer. At thisfacility, containing more than 7500 differentspecies of insects, staff examine and identifynon-indigenous species in an attempt to detectnewly introduced insects at an early stage. Inthis case, they found some six distinct speciesof exotic insects in one collection. Based onthese studies, researchers were able to deter-mine that more than 20 percent of the totalbark beetle fauna at these sites was non-native.

“There is no way of knowing whether anintroduced species is going to be harmful,”says Dr. Humble. “They have not evolved withthe plant species they’re attacking on this con-tinent. There tend to be no evolutionary checksor balances, so the plant may actually be moresusceptible to the pest.” Dutch elm disease,chestnut blight and white pine blister rust areall examples of exotic tree diseases that haveaffected native plant diversity in Canada.

“The threats posed by introduced speciesto biodiversity are immense, insidious andever-increasing,” says Gerrit van Raalte, man-ager of the Forest Biodiversity Network. “Thatis why the work of Drs. Humble and Allen isextremely important.”

At the Pacific Forestry Centre, staff aredeveloping new tools that will greatly assist intracking down non-indigenous species. Withthis information, scientists will eventually beable to assess the rate of introduction of thesespecies, determining whether these rates areincreasing or decreasing. “We have a uniqueset of circumstances here,” says Dr. Humble.“In both the Forest Health and Forest Biodi-versity Networks we’re striving to developmethods to detect introduced pests.”

Dr. Humble can be reached atlhumble@pfc.nrcan.gc.ca Dr. Allen can bereached at eallen@pfc.nrcan.gc.ca

Detecting Forest Pests

5

“W e

often don’t know

about these pests

until some time

after they’re

reached our

shores.”

Forest Health Network

Chinese longhorn beetle

Is There Life

The term old-growth often inspiresthoughts of the temperate rainforests ofBritish Columbia; western redcedar and

Douglas-fir tower amidst a vast carpet of fernsand moss-covered logs. Yet, beneath the lushcanopy of ancient forests is a complex systemfor moderating local climate change, storingcarbon and providing a fundamental habitatfor mammals, birds, fish and insects.

In the last 100 years these forests haveundergone enormous changes through harvest-ing and other disturbances. More recently, old-growth forests have been the focus of attentionfor many who fear that Canada (home to 25%of the world’s coastal temperate rainforests) isin danger of losing one of its most significantnatural assets.

Dr. Tony Trofymow, research scientist insoil ecology, and other Canadian Forest Ser-vice (CFS) scientists such as Dr. Caroline Pre-ston and Dr. Doug Goodman, have devotedtheir energies to examining changes in forestecosystems on southern Vancouver Island fol-lowing the conversion of old-growth forests tomanaged forests. As part of the Forest Ecosys-tem Processes Network at the Pacific ForestryCentre, they aim to determine whether old-growth conditions recover in older second-growth forests.

Using a chronosequence research model,scientists study changes in the nature and fluxesof carbon and nutrients with forest development(comprising the four stages of regeneration,immature, mature and old-growth), the diversityof soil fauna and flora, small vertebrates andvascular and non-vascular plant varieties. Byexamining long-term changes in the forestecosystem, CFS scientists assist foresters indeveloping forest practices that improve thecare of managed forest lands in B.C. and hencepreserve biodiversity and sustainability.

What are Chronosequences?

Imagine being able to travel ahead in timeabout 150 years to see how second-growthforests compare to today’s old-growth forests.Will they have the same characteristic plantand animal species, upholding a similarlycomplex level of ecological interaction?“Because of the nature of forests and howlong-lived they are it’s quite difficult to

6

answer these sorts of questions,” says Trofy-mow. “There are two sorts of studies you cando; you can cut down a forest and then watchfor 100 years and see what kinds of thingscome back,” but “that takes several generationsof foresters.” An easier way is to set up achronosequence which enables researchers toexamine forests at several stages of growth dur-ing a relatively short period. He describes thisapproach as “substituting space for time”.Used to conduct timber inventories and pre-dict tree growth in the forest industry, CFS sci-entists apply the chronosequence model toarrive at a more complete picture of futureforests. “Nothing has been looked at in thisparticular scale or detail probably withincoastal North America,” explains Trofymow.

Initiated by Forest Ecosystem DynamicsProgram in 1991, researchers began to look forsites to study changes resulting from convert-ing forests in the Coastal Western Hemlock(CWH) zone of southern Vancouver Island. In1992, five western hemlock dominated sitesand five Douglas-fir sites were chosen andchronosequence plots established. These sitesgave scientists a chance to observe two climat-ic extremes: the drier forest types of the zoneon the leeward side of the Island (Douglas-fir)and the wetter types on the windward side ofthe Island (western hemlock). Each of the tensites had stands inside an area of five squarekilometers or less, comprised of four ages andsimilar within environmental conditions suchas elevation and slope.

What factors does the chronosequence model take intoaccount?

The chronosequence model has three compo-nent study topics including: ecosystemdescription, ecosystem processes, and biologi-cal diversity. Ecosystem description looks atsite and soil descriptions, structural character-istics of the forest environment, and indicatorplant species.

As a soil ecologist, Dr. Trofymow is inter-ested in ecosystem processes studies whichexamine microbial activities, soil respiration,rates of decomposition, and how they vary indifferent forest stands and different stand ages.One of his main questions concerns theamounts of carbon tied up in detrital materials

“N oth-

ing

has

been looked at in

this particular scale

or detail probably

within coastal

North America.”

Forest Ecosystem Processes Network

such as coarse woody debris, the forest floor,and other organic matter, and the loss ratesand influx rates into these detrital pools. “Oneof the things we wanted to get a better handleon was how those sorts of pools changed dur-ing secondary stand succession,” he says. Anessential part of the ecosystem processes stud-ies, scientist Caroline Preston looks at howmineral soil organic matter, litter fall, forestfloor, and dissolved organic carbon are trans-formed from original plant carbon into variouscompounds, and are then lost as carbon diox-ide in the atmosphere. Dr. Preston alsoexplores the role of tannins (from various treebarks) within forest ecosystems.

The ecosystem processes studies arelinked to the Canadian Intersite Decomposi-tion Experiment (CIDET), a climate changestudy that Dr. Trofymow has led since 1992.The experiment looks at how rapidly needles,leaves, grasses, and wood decompose andrelease carbon into the atmosphere. Findingout how organic matter decomposes helpsdetermine how these releases influence levelsof carbon dioxide, a greenhouse gas connectedto global climate change.

As part of the biodiversity studies,researchers look at soil fauna such as collem-bola, plant life such as canopy lichens, andvertebrates such as salamanders to determinepossible discrepancies in different foreststands. Due to an interest in the conservationof biodiversity, CFS forest soil ecologist DougGoodman studies types and distribution ofectomycorrhizas, a symbiosis of tree roots andfungi found mostly in the forest floor. Dr.Goodman’s study concerns whether old-growth is required habitat for some species ofectomycorrhizal fungi.

How does this researchapproach benefit forestry?

The chronosequence approach provides infor-mation that can be used by provincial agen-cies and forest companies for improving themanagement of forest lands in B.C. Andbecause the study looks at varied aspects of aforest, the chances of coming up with satisfy-ing responses are great. “The chronosequencestudies undertaken by Tony Trofymow andhis collaborators clearly demonstrate the ben-efits of multi-disciplinary research needed to

7

support the forest industry’smigration to ecosystem based management,”says Bill Meades, manager for the ForestEcosystem Processes Network.

CFS scientists and other researchers willbe reporting on their results of the first fiveyears of the chronosequence experiment at aworkshop to be held at Ocean Pointe Resort inVictoria from February 17 to 19, 1998. Thismeeting will give biologists, foresters andresearchers the opportunity to share findingsfrom recent studies in coastal B.C. on theeffects of converting old-growth forests tomanaged forests. The three day workshopcalled “Structure, Processes and Diversity inSuccessional Forests of Coastal British Colum-bia” will also introduce general audiences tothe idea of using chronosequences as an effec-tive tool to conduct forest studies. Says Trofy-mow, “I think it’s going to be able to give us agood understanding that will lead into a lot ofinsights, and hopefully better forestry prac-tices in the future.”

Dr. Trofymow can be reached atttrofymow@pfc.forestry.ca. Information on theworkshop is available via the World WideWeb at http://www.pfc.cfs.nrcan.gc.ca

Dr. Trofymow checking data logger in old-growthchronosequence plot

After Old-Growth?

8

“I found only marginal evidence that anyof the 70 types of ectomycorrhizal fungi weobserved were more abundant in one age classthan the other, and no evidence that any fun-gus was specific to one age class,” he says. Dr.Goodman demonstrated that the originaldiversity of ectomycorrhizal fungi should beable to recover by the time a second standmatures, given appropriate management ofmature or old-growth stands that are close to amaturing stand.

Questions remain however about the dis-persal of ectomycorrhizae and the effects ofclearcutting on these dispersal patterns. “Wedon’t know at what age ectomycorrhizae re-enter maturing stands, and that knowledgecould be necessary for their conservation,”explains Dr. Goodman. “We also don’t knowwhat happens where a large area of forest hasbeen clearcut and old-growth patches haven’tbeen left behind. It may be important in thelandscape to maintain patches of old growth toprovide an area from which these fungi candisperse into maturing stands.”

Through his work at the Pacific ForestryCentre, Dr. Goodman collaborates with Dr.Tony Trofymow in assessing the effects onbiological diversity of converting old-growthforests to second-growth forests. Dr. Goodmanis also currently editing and contributing to apublication for forest ecologists with Dr. Tro-fymow and other researchers titled A Manualof Concise Descriptions of North AmericanEctomycorrhizae. “This manual is useful toecologists studying the effects of various forestmanagement regimes on ectomycorrhizal com-munities. In order to study a community youhave to be able to identify its members,” saysDr. Goodman.

By studying ectomycorrhizal fungi inmature and old-growth forests in B.C., Dr.Goodman and his collaborators provide agreater understanding of their functionaldiversity and the effects of different forestmanagement regimes on these symbiotic fungi.

Dr. Goodman can be reached atdgoodman@pfc.cfs.nrcan.gc.ca

“To see a world in a grain of sand, anda heaven in a wild flower.” Thesewords by English poet William

Blake bring to mind the abundance of floraand fauna thriving in the soil. Shaded bynature’s canopy, the role of these lesser knownorganisms is essential for the overall functionof forest ecosystems. One such living entity isa fungus and plant root that combine to formectomycorrhizae. Formed by almost all trees intemperate forests, these tiny structures helptrees acquire water and nutrients.

“What we have is a mutualistic symbiosisof a root of a plant and a fungus,” says DougGoodman, a biologist with the Canadian ForestService (CFS) in the Ecosystem Processes Net-work. Mutually beneficial for each partner,these ectomycorrhizal roots produce plant hor-mones that cause the morphology of the rootto be altered depending on the species of fun-gus and its host species. On the southeasterncoast of Vancouver Island, Dr. Goodman andothers studied dominant and co-dominantspecies of ectomycorrhizal fungi and a largenumber of less common species in mature andold-growth stands of Douglas fir.

His study showed that mature stands(about 80 years old) had acquired an ECMflora very similar to that of old-growth stands,at two sites where the old growth was adjacentto mature stands.

Studying the World Underfoot

“W hat

we

have is a mutualistic

symbiosis of a root of

a plant and a fun-

gus.”

Ectomycorrizae – a mutualistic symbiosis of a fungus and plant root

Ecosystem Processes Network

It may sound like a new design for yourveneered coffee table, but laminated root rotis not something you want associated with

your home.

Caused by the fungus Phellinus weirii,laminated root rot (LRR) causes wood to decayand separate along annual rings as laminations(hence the term, “laminated root rot”). It is oneof the most damaging root diseases affectingDouglas-fir in northwestern North America,reducing timber volume and growth by mil-lions of cubic meters annually.

“There are a number of fungi that causeroot diseases in B.C. but P. weirii is the majorroot pathogen on the coast,” explains RonaSturrock, researcher in the Canadian ForestService Effects of Forestry Practices Network.“While LRR has been a natural component ofcoastal ecosystems for thousands of years, itsincidence in our forests, particularly in man-agement stands, has been increased by severalfactors such as the restocking of infected siteswith only Douglas-fir, and in the loss of anative, LRR-tolerant conifer, white pine towhite pine blister rust.”

Like many root diseases, LRR spreads viaroot contact and can survive in stumps androots for decades, acting as inoculum for sub-sequent rotations. There are several manage-ment strategies for LRR, most of which are bestconducted at the time of stand regenerationwhen inoculum can be reduced through stumpremoval or other means, or when tree specieswhich are immune (or have a low susceptibili-ty to the fungus) can be planted.

Sturrock and other researchers at thePacific Forestry Centre are trying to determineif there are any Douglas-fir families that aremore tolerant to LRR than others. It is the firstscreening study of its kind involving P. weirii.

“A few years ago we developed a tech-nique for inoculating seedlings,” explainsSturrock. “That research, and funds providedrecently by Forest Renewal B.C., have enabledus to conduct our current study with materialprovided by the B.C. Ministry of Forestsunder their Douglas-fir Tree Improvement Pro-gram. We are hoping to provide B.C. Ministryof Forests with information on disease toler-ance so they can build it into their breedingprogram.”

“The Douglas-fir Tree Improvement Pro-gram is a breeding program for coastal Douglas-fir,” adds Mr. Jack Woods, research scientistwith the Ministry of Forests. “We are hoping tofind and promote tolerant Douglas-fir families.We provided the Canadian Forest Service with97 families of Douglas-fir of which we knowthe genetic history. We hope to apply theresearch to our breeding program.”

For each of the 97 Douglas-fir families, 36seedlings were inoculated, adding up toapproximately 3500 inoculated trees. Theseedlings that have survived are now fiveyears old.

“To discover if there are any family-relat-ed trends, we are studying seedlings that werenot killed or infected by P. weirii,” said Stur-rock. “We have found that every family hadseedlings that had been killed or infected bythe fungus, so it appears that, at least so far,none of the families are resistant to LRR. But itappears that some have a stronger tolerance toP. weirii than others. Of course, these are onlypreliminary results; our study is still on-going.”

If this research provides evidence of Dou-glas-fir tolerance to the fungus, the next stepin the project would be to screen candidatefamilies against a variety of P. weirii isolates toconfirm tolerance and determine how broadthat tolerance is. The ultimate goal of theresearch is to enable the production of toleranttrees for diseased sites where Douglas-fir is thepreferred species.

Rona Sturrock can be reached atrsturrock@pfc.cfs.nrcan.gc.ca

Root Rot Research Reveals Results

9

“I t is one of

the most

damaging

root diseases affect-

ing Douglas fir.”

Effects of Forestry Practices Network

A young tree damaged by laminated root rot

Tree height estimates are critical to forestinventories. They show how well a standis growing and make possible a good

estimate of the amount of wood it contains.But aerial photo interpretation is not veryaccurate for tree heights, and measurementstaken from ground level are expensive and dif-ficult to obtain.

“We’ve found a way to use airborne lasersfor reliable estimates of tree height,” saysCanadian Forest Service scientist Dr. SteenMagnussen, working in the Landscape Man-agement Network. “We were able to interpretthe foliage signals with the help of exact treemeasurements on the ground.”

Laser data from terrain mapping haveoffered foresters a tantalizing possibility. Inthe last decade, airborne laser scanning hasbecome the technology of choice for terrain

mapping, because of itsspeed and accuracy andits ability to penetrateforest canopies and givea clear ground signal. Asingle laser pulse typi-cally produces both aclear ground reflectionand, somewhat aboveit, a less distinct reflec-tion from contact withfoliage. These vegeta-tion signals are dis-carded by terrainmappers. Foresterswant to know aboutthe canopies creat-ing these reflec-tions. But the pat-terns of reflectionhave resisted inter-pretation.

The difficultyis that the laser pulse can hit

anywhere on the canopy. Whereas the groundreflections show a clear connected surface, theleaf reflections, when plotted, occur in a“cloud” at various levels throughout thecanopy.

Magnussen’s group decided to take a closelook at these canopy reflections under con-trolled conditions. They used the 36 plots inthe Shawnigan Lake fertilizer and thinning

trial, which has collected precise data oncanopy structure to test the results of variousgrowing techniques. By flying a laser scan ofthese plots, they were able to compare thecanopy laser reflections with exact measure-ments of the canopy structure.

Magnussen found that, on average, thevegetation hits reflected the canopy of thestand. The average height of the leaf reflec-tions above the ground was about equal to theheight of the mean of the leaf area, so therewas as much leaf area above as below thereflection mean. Furthermore, the vertical pro-file of laser hits corresponded closely or rea-sonably to the vertical profile of the canopy in25 of the 36 plots.

“Of course, inventory agencies care moreabout tree height than leaf area,” says Mag-nussen. “So we had to find a way of estimatingtree height from the cloud of canopy hits. Thebig variable is tree density. With tightlypacked trees, the maximum tree heights willclosely match the highest laser hits, but withwidely spaced trees, there may be few or notreetop hits. So we’ve worked out a simpleprocedure in which the forester just addsinformation on stems per hectare in the standand applies it to the profile of laser reflectionsto estimate an average maximum tree height.”

Dr. Murray Strome, manager of the Land-scape Management Network, explains, “Accu-rate forest inventories are essential for plan-ning and monitoring forest management at alllevels. These range from the local level for har-vest planning, silviculture, wildlife manage-ment and erosion/pollution control to thelandscape on the provincial level for establish-ing broad policies such as “Annual AllowableCute”, and at the national level for monitoringthe Criteria and Indicators of sustainable forestmanagement.”

Magnussen’s group plans to launch fur-ther tests. But in view of the need and theready availability of information from terrainmapping, he sees immediate use for themethod. Moreover, as terrain mapping projectsreach completion, scanning companies may beable to add tree height estimation as a new andvalued service.

Dr. Magnussen can be reached at smag-nussen@pfc.cfs.nrcan.gc.ca

Light on Canopies

10

Landscape Management Network

“W e

have

found a way to use

airbourne lasers for

reliable estimates of

tree height.”

A partial aerial view of the Shawnigan Lake

trial as “seen” by the laser scanner

Staff Comings and Goings

Sen Wang joins the PacificForestry Centre as a foresteconomist. Specializing inforest economics and policy,Sen will focus his research onCanada’s competitiveness inthe international forest prod-ucts market in comparisonwith forest-dominant jurisdic-tions in the Pacific Rim andelsewhere. He holds a masterof science degree from theUniversity of British Columbia (UBC), and is currently acandidate for a doctoral degree at UBC in forestresources management.

Florence Scott has recently retired after 32 years withthe federal government. Florence worked at the PacificForestry Centre as Human Resources Manager for over 17years, coordinating and implementing the human

resource program. She also advised senior managementand staff on the interpretation and application of poli-cies, regulations, collective agreements, directives andthe resolution of human resource dilemmas.

Welcome to David Broad whotakes over for Florence Scottas Manager of HumanResources. David joins usfrom Fisheries and Oceans,Pat Bay where he was HumanResources Manager.

Guy Gondor leaves the Pacific Forestry Centre after 10years. As Chief, Informatics, Guy was responsible for theoperation and management of the computing centre.

RecentPublicationsA method for estimating canopyopenness, effective leaf area index,and photosynthetically active pho-ton flux density using hemispheri-cal photography and computerizedimage analysis techniquesFrazer, G.W.; Trofymow, J.A.;Lertzman, K.P.Information Report BC-X-373. PacificForestry Centre, Victoria, B.C. (1997)

Les ressources canadiennes en bio-masse forestière: estimations à par-tir de l'inventaire des forêts duCanada.Penner, M.; Power, K.; Muhairwe,C.; Tellier, R.; Wang, Y.Rapport d'information BC-X-370F. Cen-tre de foresterie du Pacifique, Victoria,Colombie-Britannique. (1997)

The Bridge. September 1997.Maides, R. (Editor)First Nations Forestry Program. Natural

Resources Canada, Canadian Forest Ser-vice/Indian and Northern Affairs Cana-da. Pacific Forestry Centre, Victoria BC.(1997).

Ferns. Forest ecosystem researchnetwork of sites.Anon. (Brochure) Natural Resources Canada,Canadian Forest Service, PacificForestry Centre, Victoria BC. (1997).

A field estimation procedure fordowned coarse woody debris.Taylor, S.W.Technology Transfer Note No. 2. Cana-dian Forest Service, Pacific ForestryCentre. (1997).

Une methode d'evaluation sur leterrain des debris ligneux grossiers.Taylor, S.W.Note de Transfert Technologique.Numéro 2. Service canadien des forêts,Centre de foresterie du Pacifique. (1997).

A review of tree wounding.Nevill, R.J. Technology Transfer Note No. 3. Cana-

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dian Forest Service, Pacific ForestryCentre. (1997).

Aperçu des blessures des arbres.Nevill, R.J.Note de Transfert Technologique.Numéro 3. Applications de la rechercheforestière. Service canadien des forêts,Centre de foresterie du Pacifique. (1997)

Predicting forest floor moisture con-tents from duff moisture code values.Lawson, B.D.; Dalrymple, G.N.;Hawkes, B.C. Technology Transfer Note No. 6. Cana-dian Forest Service, Pacific ForestryCentre. (1997).

Decay associated with logginginjuries in Western Larch, Larixoccidentalis, and in LodgepolePine, Pinus contorta.Allen, E.; White, T.Technology Transfer Note No. 7. Cana-dian Forest Service, Pacific ForestryCentre. (1997).

A more complete list of recent publica-tions is available via the World WideWeb at: http://www.pfc.cfs.nrcan.gc.ca

Sen Wang

David Broad

Upcoming EventsProfessional Foresters for 50 Years - LearningFrom the Past to Shape the FutureMarch 4 - 6, 1998Victoria, B.C.

The Association of B.C. Professional Forestersis celebrating a major milestone in 1998 withtheir fiftieth Annual General Meeting. Themeeting will focus on the celebration with areview of activities and accomplishments overthe last fifty years, combined with a look tothe future and what the next fifty years mightpresent to the profession of forestry. The pro-gram is designed to be of interest to bothforesters and non-foresters and everyone iswelcomed to attend.

Contact:Chris Lee,Canadian Forest Service,Pacific Forestry Centre506 West Burnside Road,Victoria, B.C. V8Z 1M5Telephone: (250)363-0792Fax: (250)363-0775E-mail: clee@pfc.cfs.nrcan.gc.ca

Automated Interpretation of High Spatial Resolution Digital Imagery for ForestryFebruary 10 - 12, 1998Victoria, B.C.

The Canadian Forest Service Landscape Man-agement Network is holding a forum of papersand discussion sessions on computer-assistedmethods of forest interpretation and parameterextraction from high resolution digitalimagery. Participants will be scientists, tech-nology developers, forestry practitioners, andforest managers. Concentration will be onforestry requirements, current capabilities andfuture activities.

Contact:Don Leckie,Canadian Forest Service,Pacific Forestry Centre506 West Burnside Road,Victoria, B.C. V8Z 1M5Telephone: (250)363-0624Fax: (250)363-0775E-mail: dleckie@pfc.cfs.nrcan.gc.ca or checkhttp://www.pfc.cfs.nrcan.gc.ca

Structure, Processes and Diversity in Succes-sional Forests of Coastal British ColumbiaFebruary 17 - 19, 1998Victoria, B.C.

The main purpose of this workshop is to sharefindings from recent studies in forest types ofcoastal B.C. on the effects of converting old-growth forests to managed forests, how variousecosystem attributes change during stand succes-sion and the extent to which they are restored asforests mature. Topics include: changes in standstructure and composition; site carbon and nutri-ent balance; and species diversity.

Contact: Rod Maides,Canadian Forest Service,Pacific Forestry Centre506 West Burnside Road,Victoria, B.C. V8Z 1M5Telephone: (250)363-0737Fax: (250)363-6006E-mail: rmaides@pfc.cfs.nrcan.gc or checkhttp://www.pfc.cfs.nrcan.gc.ca

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I N F O R M A T I O N F O R E S T R Y

Published by

Pacific Forestry CentreCanadian Forest Service

Natural Resources Canada506 West Burnside Road, Victoria, B.C., V8Z 1M5

(250) 363-0600

Editor: Joanne StoneLayout: Jennifer Adsett

Writers: Lissa CowanJoanne Stone

Articles from this issue may bereprinted without permission.

We would appreciate notification ifour material is reprinted.

For further information:Phone: (250) 363-0606

Fax: (250) 363-6006Email: jstone@pfc.cfs.nrcan.gc.ca

Information Forestry is also downloadable from our site at www.pfc.cfs.nrcan.gc.ca