Short rotation forestry as a source of energy

Short rotation forestry as a source of energy


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Commission of the European Communities
EUR 12632 EN
Blow-up from microfiche original Commission of the European Communities
Agricultural Institute
Oak Park, Carlow
Contract No. EN3B-0039-IRL
(1.04.1986 to 31.05.1989)
Directorate-General Science, Research and Development
1990 CLEUR 12632 EN Published by the
Telecommunications, Information Industries and Innovation
Neither the Commission of the European Communities nor any person acting on behalf
of then is responsible for the use which might be made of the following
Catalogue number: CD-NA-12632-EN-C
© ECSC — EEC — EAEC, Brussels - Luxembourg, 1990 Ill
Orig nally it was envisaged th t f 1 wood c u be grown
economically on poor qu lity s il, of which large ar as occur in
several EC countries. This project has shown that a yield of 15
- 18 t.D.M. ha~ annum- can be obtained from s ort r tation
coppice fore try over at least 4 harv stin s. The experience of
basket willow growers is th t such a plant tion will survive for
20 - 30 years. Initially the best yielding species was S lix
aquatica g'gantea (more r tly r named S. bur] ica) but this
has now been severely atta k d all o er Europe by the rust
fungu Mel s ra spp. The Poplar cl ne ap h al ome
infected by this disease, but to a much les er ext nt. Better
yielding, and more di ea e re ' tant cl s of poplar and willow
are now available.
Since this project began in 1977, a surpl of many
agricultural products has developed not only in the EC
countries, but also in North America and Scandinavia. It is
difficult to f nd an economic use for this surplus land. One
possibility which must now be seri usly considered i en rgy
crops, including Short Rotation Forestry (SRF). On better
quality land, poplar will usually outyield willow, but the
coppicing ability of the newer genetically-improved poplar
clones h s yet to be proven.
The introduction of an exotic crop into an area creates a
new environment for certain insect specie . These can become
pests, but ev ntually these ar controlled to an extent by their
natur 1 enemies. In this project, four inse t pests ppe red:
Croesus s pt trionalis in Alnus, Opteroperopter brumata in
willow, Phyllodecta vulgtis una in some cl n s of willow, and
Cryptorhyn us 1 p thi in willow and poplar. The first two have
been larg ly controll d by natural enemies. At Clon ast, adult
Phyllodecta survive the winter, and therefore require to be
controlled by spr ying. This p t is not a problem at Oak Park,
possibly because some natural enemies occur. N t all willo
clon s are susceptible. Cryptorhynac us lapathi was rec rded at
only one centre, but is a serious problem in poplar in North
The most critical part of the entir system is weed control
at the regrowth stage. Although, some useful pr ress has been
made, the m tter requires further study.
A systems analysis inc rporating all necessary treatments
shows that on poor quality soils such as Atlantic blanket peat,
SRF is un nomic unless more productive species can be found
than are at present available. At the other centres, including
mined-out peatland, SRF can be produced at a competitive co t.
Methods and costs of harvesting have not yet been d termined,
and th se are now probably the most critical fa tor in the
introduction of SRF.
The system is envir nmentally positive SRF planta o s
increase the range of song and gamebirds. The resultant fuel is
low in sul hur and arsenic, and so could help to ov rcome the
problem of air pollut'on which is now a problem in many European
cities. CONTENTS
Summary III
M. Neenan
1. Introduction and methodology 1
M. Neenan
2. Species and clone trials on marginal land 6
M. Neenan
3. General conclusions on the suitability of different species
for the production of SRF 26
M. Neenan
4. Silvicultural trials on SRF 30
M. Neenan
5. Properties of short rotation forestry5
M. Neenan
6. Pests and diseases 4
M. Neenan, T. Kennedy, B. Dunne
7. Systems analysis
M. Neenan, S. Power
8. Short rotation forestry on good agricultural soils 49
M. Bulfin
9. Bird survey of the SRF plantations at Clonsast 60
B. Kavanagh
10. General conclusions 68
References 71
Acknowledgements8 VI
PLate 1 - Landscapes of original trials 3
Plate 2 - Aerial view of the landscape near Carlow 5
Plate 3 - Variations in typical midland bog 19
Plate 4 - Glenamoy type lamdscape 26
Plate 5 - Nelder trial on S. Viminalis at Clonsast 31
Fig. 1 (a) - Geographical location of experiments 4
(b) - Peatland areas in Ireland
Fig. 2 - Survival of different species and clones
at Oak Park after coppicing 10
Fig. 3 - Yield tonnes ha/annum of nine species
grown at Oak Park 1977 to 19882 Section 1 INTRODUCTION and METHDDCIJOGY
1.0 Introduction
Following the oil crisis of 1974/75, a nuniber of options
for harnessing solar energy were inaugurated by the E.C. In
northern latitudes the unequal day length precluded the use of
certain systems; in these areas the best possibility lay
in the harnessing of photosynthesis. The choice of plants
for this purpose is wide; Neenan (1) cited 35 species of plants
within the British flora which could be utilised in this regard.
Many of these have since been studied by other investigators.
There are three main criteria in the use of biological sources
of energy:
(a) the material must not be so widely dispersed that
the energy of assembling it nearly equals its
calorific value,
(b) it must be available on a predictable basis rather than
as a by-product of another activity, and
(c) it must be cost effective using normal discount rates.
These arguments add up to the idea of a crop which is
specially grown for energy purposes, convenient to
harvest (i.e. terrestrial) and high in dry matter
content. One such crop is Short Rotation Forestry (S.R.F.).
This present report concerns the use of Short Rotation or
Coppice Forestry. Since the project has extended over a period
of 12 years, it may be useful to summarise the results as a
whole, rather than those of the most recent contract.
1.1 Short Rotation Forestry
Co[pico Jon\slry i.e. harvesting shoots at intervals of
3-10 years, has been known since Roman times. In the early
1960's, the method was investigated in Georgia, USA as a
potential source of paper (2)(3)(4)(5). The resulting material
was promising as a source of cardboard, particle board,
hardboard and some types of paper (5). Yields were appreciably
higher than those from high forest at the same sites (6). 1.2 Objections to SRF
In 1976 and 1977, when the effects of the oil crisis were
becoming evid nt, agricultural production in the EC was
reasonably in equilibrium with demand. There was, therefore, a
tendency in some countries to dismiss the idea of energy from
biological sources for the reason that the necessary land
resources were not likely to become available. Three of the
then EC countries, Ireland, France and the UK seemed to have a
potential surplus of low grade land which could be used for this
purpose (7). Within the past few years the position has been
reversed, and there is now an active programme of phasing first
class land out of agricultural production. The principal
argument made against energy from biomass is therefore no longer
1.3 Land availability
Initially it was expected that in Ireland the land becoming
available would be from the following soil types:
(A) Second class (i.e. slightly wet) agricultural soils,
(B) Deep fen type peat either in virgin state (Bl) or after
most of the peat had been removed (B2),
(C) Blank t (Alpine) peat on the Atlantic coast,
(D) Wet hill land (Drumlin) in the north-west of Ireland, and
(E) Acid podzols on Old Red Sandstone in the south.
1.4 Location of the experiments
The landscape types are shown in Plate 1. The initial
experiments, using 12 species/clones, were established in 1977
jointly with the State Forest Service. At the end of the first
three year period it became clear that soils Bl and C, would in
their unimproved state, not support SRF (8). At site C,
the acid podsol conifers grew reasonably well, but the broad
leaved species tended to die out. It was assumed therefore, that
rather than using high rates of lime and fertiliser, it would be
more economic to have this site utilised by conifers rather than
by SRF.