Alley Coppice : an innovative agroforestry system that combines

timber and energy wood production

Dupraz C., Tosi L., Paris P., Facciotto G., André J.,

Graves A., Lunny R., Morhart C., Nahm M.

Christian DUPRAZ, Jérémy ANDRE  : Institut National de la Recherche Agronomique FranceLuca TOSI, Piero PARIS : Consiglio Nazionale delle Ricerche; ItalyGianni FACCIOTTO : CRA- PLF ItalyAnil R. GRAVES : Cranfield University United KingdomRory LUNNY : Teagasc –, IrelandChristopher MORHART : Albert-Ludwigs-University Freiburg, GermanyMichael NAHM : Forest Research Institute Baden-Württemberg, Germany 

 

Two options available :

Competition : Short Rotation Coppice, Afforestation, Annual crops for energy (cereals, oilcrops..)

Complementarity :

Biomass from food crop residuesAgrivoltaismAF systems that produce energy from trees and food from crops (or the reverse)

Food versus Energy :

the « competition for land » issue in Europe

Agrivoltaïsm

Biomass for energy from trees in AF systems ?

Two ways :

● Energy from coppiced trees : SRC (Short Rotation Coppice)

● As the intercrop● On the tree line

● Energy from standard pollarded trees : dual purpose trees (timber-energy)

To mix or not to mix, that is always the question

Indicators of the productivity of mixtures

• Land Equivalent Ratio LER (Mead and Willey, 1980)

• LER = Sum (Relative Yields) = RYtree + RYcrop

Indicators of the productivity of mixtures

• Range of LER values :– 0.9 to 1.1 for mixtures of annual species– 1.0 to 1.2 for legumes/non legumes annual species–– ? in silvoarable agroforestry– ? in agrivoltaism–– Unknown for SRC-AF systems– Unknown for Pollarded trees – AF systems

»

1.36Measured LER

Poplars-winter cereals, 14 years rotation

Predicted modelled LER

Tree density Pruning height

Tree row orientation

1.2 to 1.6

Agrivoltaïc LERs

measured :

1.5 to 1.7

Indicators of the productivity of mixtures

• Range of LER values :0.9 to 1.1 for mixtures of annual species1.0 to 1.2 for legumes/non legumes species

1.2 to 1.6 in silvoarable agroforestry1.5 to 1.7 in agrivoltaism

Unknown for SRC-AF systemsUnknown for Pollarded trees – AF systems

»

Energy from AF systems :

1. The SRC intercrop option

Energy from AF systems :

1. The SRC intercrop option

The concern :

LERs for SRC-AF may be much lower...

than LERs for annual crops-AF

Simultaneous planting of timber trees

and SRC

France

Germany

Italy

Some results from our oldest experimentResults presented were obtained in a 7-year old experimental field, located in Northern Italy.

This has Pyrus and Sorbus as timber trees, and poplar SRC grown in a two-year rotation cycle.

Gianni Facciotto and colleagues

CNR, Casale-monferrato, ItalyCNR, IBAF, Porano, ItalyUniversita di Torino, Italy

Site of experimental trial: Casale Monferrato – AL

Lat: 45°08' N Long: 8°30’ E

Alt: 106 m a.s.l.

1

Timber trees

Pyrus and Sorbus clonespropagated in vitroculture (Univ. Milano)

Short Rotation Coppice

Poplar clones:Populus deltoides Lux

P. deltoides Oglio P. ×canadensis Triplo

Pure PearPure Sorbus

Near PearNear Sorbus

Between PearBetween Sorbus

0,0

10,0

20,0

30,0

40,0

50,0

60,0

Db

Hm

m Timber tree growth

Pure = Trees without SRC - Near = Trees with SRC only on one side Between = Trees with SRC on both sides

Short Rotation Coppice yields

Triplo Oglio Lux0

2

4

6

8

10

12

2008

2010

2012

Clones

Bio

mas

s (t

ha-

1)

Oven dry tons per hectare

Sensitivity to SRC competition varies between tree species

Reduction of timber trees growth by SRC competition not correlated to SRC productivity

Conclusions :

Improved and very productive SRC-AF possible

LERs of SRC-AF not yet available (modelling in progress)

Energy from AF systems :

2. The Pollarded trees option

31/03/2013

10/10/2013

Modelling pollarded trees AF systems with the Hi-sAFe model

Timber growth stopped

(but contradictory with field observations during the first year after pollarding)

Branches growth stimulated

Crop yield sustained

Time of first pollarding

RYs of AF systems with standard or pollarded trees

RYs Trunk Branches Crop

StandardPollarded

Pure forestryPure crops

0.620.18

10

1.11.84

10

0.680.81

01

Hi-sAFe model, André, Molto, Dupraz, in prep

Standard Pollarded

Crop & branches 1.78 2.65

Crop & timber 1.31 0.99

LERs of AF systems with standard or pollarded trees

Agroforestry systems with pollarded walnut trees

First evaluation by modeling and field monitoringJ. André, Q. Molto, G. Talbot, L. Dufour, J-F Bourdoncle, A. Sellier, C. Dupraz

Poster available.... please pay us a visit !

Take home Conclusions :

SRC-AF may have intermediate LERs (profitability to be assessed)

Pollarded trees-AF may have very high LERs

Farmers were wise....

Thank you for your attention