1. 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 France
Luca TOSI, Piero PARIS : Consiglio Nazionale delle Ricerche; Italy
Gianni FACCIOTTO : CRA- PLF Italy
Anil R. GRAVES : Cranfield University United Kingdom
Rory LUNNY : Teagasc –, Ireland
Christopher MORHART : Albert-Ludwigs-University Freiburg, Germany
Michael NAHM : Forest Research Institute Baden-Württemberg, Germany

3. Two options available :
Competition :
Short Rotation Coppice, Afforestation, Annual crops for energy (cereals,
oilcrops..)
Complementarity :
Biomass from food crop residues
Agrivoltaism
AF systems that produce energy from trees and food from crops (or the reverse)
Food versus Energy :
the « competition for land » issue in Europe

4. Agrivoltaïsm

5. 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)

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

7. Indicators of the productivity of mixtures
• Land Equivalent Ratio LER (Mead and Willey, 1980)
• LER = Sum (Relative Yields) = RYtree + RYcrop

8. 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
»

9. 1.36
Measured
LER
Poplars-winter cereals,
14 years rotation

10. Predicted
modelled
LER
Tree density
Pruning height
Tree row orientation
1.2 to 1.6

11. Agrivoltaïc
LERs
measured :
1.5 to 1.7

12. 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 species
1.2 to 1.6 in silvoarable agroforestry
1.5 to 1.7 in agrivoltaism
Unknown for SRC-AF systems
Unknown for Pollarded trees – AF systems
»

13. Energy from AF systems :
1. The SRC intercrop option

14. 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

16. Simultaneous
planting of
timber trees
and SRC

17. France
Germany
Italy

18. Some results from our oldest experiment
Results 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, Italy
CNR, IBAF, Porano, Italy
Universita di Torino, Italy

19. Site of experimental trial: Casale Monferrato – AL
Lat: 45°08' N
Long: 8°30’ E
Alt: 106 m a.s.l.
1

20. Timber trees
Pyrus and Sorbus clones
propagated in vitroculture (Univ. Milano)
Short Rotation Coppice
Poplar clones:
Populus deltoides Lux
P. deltoides Oglio
P. ×canadensis Triplo

21. Pure Pear
Pure Sorbus
Near Pear
Near Sorbus
Between Pear
Between Sorbus
0,0
10,0
20,0
30,0
40,0
50,0
60,0
DbHmm
Timber tree growth
Pure = Trees without SRC -
Near = Trees with SRC only on one side
Between = Trees with SRC on both sides

22. Short Rotation Coppice yields
Triplo Oglio Lux
0
2
4
6
8
10
12
2008
2010
2012
Clones
Biomass(tha-1)
Oven dry tons per hectare

23. 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)

24. Energy from AF systems :
2. The Pollarded trees option

27. 31/03/2013

28. 10/10/2013

29. 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

30. RYs of AF systems with standard or pollarded trees
RYs Trunk Branches Crop
Standard
Pollarded
Pure forestry
Pure crops
0.62
0.18
1
0
1.1
1.84
1
0
0.68
0.81
0
1
Hi-sAFe model, André, Molto, Dupraz, in prep

31. Standard Pollarded
Crop & branches 1.78 2.65
Crop & timber 1.31 0.99
LERs of AF systems with standard or pollarded trees

32. Agroforestry systems with pollarded walnut
trees
First evaluation by modeling and field monitoring
J. André, Q. Molto, G. Talbot, L. Dufour, J-F Bourdoncle, A. Sellier, C. Dupraz
Poster available.... please pay us a visit !

33. Take home Conclusions :
SRC-AF may have intermediate LERs
(profitability to be assessed)
Pollarded trees-AF may have very high LERs
Farmers were wise....

34. Thank you for your
attention