Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 37
Multiple Uses of
Forest Trees
Many agricultural species are grown for single products and for
specialized uses, but forest trees are often grown for more
than just pulp or timber, and even those products have
multiple end uses.
Because genetic variability has been demonstrated
in most of the growth, morphological, and anatomical properties of
trees, the economic values for which trees are managed can depend on
their genetic variability. It also seems clear that the wide range of
management systems and intensities that have already been applied to
trees and forests have some influence on their genetic variation.
BENEFITS OF TREES AND FORESTS
Forests and trees provide a variety of benefits to humans. Those
benefits can be divided into two major categories: direct and indirect
benefits (Burley, 1987~.
Direct Benefits
Direct benefits and uses include forest products of economic impor-
tance, such as sawtimber and numerous other construction materials,
fodder, and fuelwood. Trees have been used throughout the world for
millennia, and today over one-half of the wood used each year is burned
for heating and cooking. In some countries in Africa, for example, 70
percent or more of the total energy used is provided by wood (Table 2-
1~.
37
OCR for page 38
~ / ~! Me
County
TABLE 2~1 Sham of Total Enemy U~ Domed by
Wood, fled Cannes' beady lions
-
W-d S~ha~ of To~1
Envy U
Mica
Kenya
^ .
Dugan
Nigeria
. ~ .
Awns
land
^ . ..
Buying
Asia
China
. . .
,.
.~^~
4..~,~
,
.o~es~a
Ne~1
,.
Stir America
8~azil
~ a.
gosh ace
Nicaragua
~~gua~y
71
82
92
93
96
>2
S3
50
94
an
~ lndude~ a~hcu~ltu=~1 Hastes and darn% in addition to Used and
. ~ ~
charcoal.
SOURC-E: S. Poster and L. Heirs. 1S8. Represent the Bash.
~o~d~tch Mar ax. Shin ton, D.C.: ~o3~d~atch ~I!ns~tc.
Repdn~d Hitch permission.
Cutrent gIo~1 flood p~~duc~on ap~p~ximates 1.5 billion amp annually
Able 2^2), as recorded in nabona1 government statistics. but the use
of add~itiona1 vast quantities of wood goes u~n~=co~rd^. Another Coup
of Food uses comprises reconstituted and ~assemb~d wood, i.nclud~in~
. ~
veneers, chip boa fiberboard, pulp, and paper. Total ~o~1 trade in
pair products approximates ~ Lion off imports and exports (food
am A~d~ltu~e Orya~qiza~on !9~)
lag JESUS O: pang plums prudes Lame to nations ~on-
omies and individuals. This type of e=~lov~ent is often seasonal and
. . ~ , ,
provides Oxfam income Then seasonal onion ~o!/kl~oads are low.
The haresEng/ sailer and pro~ss~in~ off Ducts Am ages in co~mbi-
nation glitch arming also reduce the asks associated With incomes based
on one or To cash maps.
The number of products provided by trees w~o~r~ld~ide is extensive.
He mood, bag, leaves, 6), seeds, and Cots of ages geld gods
fodder, shelter, medicine, afar/ resins, oils/ and numerous other
l. ^ .....
OCR for page 39
Multiple Uses of Forest Trees / 39
products used for subsistence and industrial purposes. In some countries
the products from trees are important contributors to individual, village,
and national economies (Myers, 1983a). Forest products can serve as
feedstocks to support a wide range of local and commercial industries,
drugs, food for human consumption, and fodder for animals (Panday,
1982; Parkash and Hocking, 1986~. In India, Myers (1988) estimates the
amount of annual revenue derived from such minor forest products is
$200 million. This equals or exceeds India's revenue from wood extracted
from the forests.
Management of forests for this variety of uses ranges from intensive
cultivation on large industrial tracts, such as in the southeastern United
States, to purely exploitative extraction with no plans for forest regen-
eration. In some societies, nuts, leaves, bark, roots, latex, and various
other parts of trees are collected as semidomesticated agronomic crops.
In the western Amazon, for example, tapping rubber and collecting
Brazil nuts are combined in forests, known as extractive reserves, that
may provide income while conserving the tropical forest ecosystem
(Cowell, 1990; Pearce, 1990~.
TABLE 2-2 World Production of Industrial
Roundwood, 1985a
Share of
Volume Total
Country(million m3) (percent)
United States347 23
Soviet Union275 18
Canada165 11
China/Taiwan93 6
Brazil58 4
Sweden49 3
Finland39 3
Japan33 2
Malaysia32 2
France29 2
All others383 26
World total1,503 100
a Industrial roundwood is defined as logs, pulp, and other raw
materials used to manufacture wood products.
SOURCE S. Postel and L. Heise. 1988. Reforesting the Earth.
Worldwatch Paper 83. Washington, D.C.: Worldwatch Institute.
Reprinted with permission.
OCR for page 40
: :~: : : :~::: :::::~: ::::::::::~::~:~:::~::~. ::: .::~: A::. :~:~:~:~:~ :~aa~a~a~aaaa~a~aa~a~a~a. ~.aaa~aa
/
A Sharps Olin the cenb~lh~ ~ ad e Con of Nepai~ca~des Adder Cam
woo ^ ad on a nearby hillside to ~ed~li~es~k. Fodder can be an impotent
pan of~househo~ld income, butits overcol~lecdo~n in areas of high p~pJ~labon
density can cause sedousda ~ guts nea~rby:~res~. Credit: Steve!n Ki~n~.
~lnd~ecibe~ne~Ctsof~esinclu!deenvi.ronmen~lpro~ctio~nand.a~=enilv
(soc~T)va~lues.Tteesconidb~teto the s~sta~inabi~Ii~ty ofland prod~ctivii
by co~nthbu ~ ~ to the for~natBon,structure, and fertility ofsoi~lin~man)
Says Po!r exam pie, they form sy~nibi~o~tic relationships v~i~tb nutien~t-
ibso~bt~g fungi off nitoogen~Fx~i~n.~ bacte-da and fungi, arid moderate
grater Boat and loss v~hile-bindin~ soils to prevent eros~o-n Trees also
contribute significantly to reducing greenhouse gases and associated
ldbalte~m~perab~re rises by conve~rurg~:caYbo~n dioxide to carbohydrate
through p~hotos~yntiesis and then locking it up v~-it~b.i.n their structures.
l]>ein~direct costs ofign~ohn~g the protection p:rovidedio the ecosystem
by healthy forests can be ve~y:bigh. Deforests don and poor cu.ltitatio~n
Prances have been cited as mayor causes fo~rd~ra~mabc dsesin sediments
in dversysfems around the Torrid (Poster, 19S9~. lncrea~sed sedimentation
into reservoirs as a result of soil runoff is dramadcaIly reducing the lid
span of several hydr~icctdc dams. in The Philippines, it is estimated
that sedi~=entabon rates in two re~rvo:irs increased by moire than 1
OCR for page 41
Multiple Uses of Forest Trees / 41
percent between 1967 and 1980. As a result, the life span of the
Philippine Ambuklao Dam project has been cut in half. A similar process
is occurring in Costa Rica, where siltation may significantly reduce the
lifetime energy production of the Cachi hydroelectric project (Poster
and Heise, 1988~.
Forests are much more than an assemblage of woody trunks with
leafy canopies. Trees determine the structure and organization of forest
ecosystems, which provide habitat for a multitude of species of plants,
animals, and microorganisms used directly and indirectly by humans.
Species diversity itself may be considered an indirect product of forests,
especially in the tropical moist forests, which contain at least one-half
of all known plant and animal species (Food and Agriculture Organi-
zation, 1985c).
The amenity benefits of forests and trees include scenic beauty, the
opportunity to view wildlife, and access to wilderness areas for study
and recreation. It is widely accepted in developed countries that such
amenity resources should be made available by the government for the
benefit of the people, possibly with direct user fees as well as with
indirect contributions through taxes. In developing countries, govern-
ments are realizing, however, the importance of natural resources,
particularly forests and wildlife, in attracting tourists and foreign
exchange. Trees also serve as cultural and religious symbols. One
example of this is the sacred forests and tree species that are found in
India and other countries in Asia.
IAND USE SYSTEMS INVOLVING TREES
Land use systems form part of the full spectrum of uses of forest
trees. A variety of land use systems incorporate either deliberately
planted or naturally occurring trees. These systems can be divided into
three major types: natural vegetation management, agroforestry, and
industrial plantation forestry, each of which produces major benefits.
The first type of system does not usually involve selection of trees with
a specific genetic composition (genotypes) or any other direct manage-
ment of genetic variability, whereas the second and third types use
mixtures of genotypic selection (and occasionally direct breeding) and
indirect genetic management.
Natural Vegetation Management
Conservation, protection, or management of naturally occurring for-
ests to preserve their biotic integrity is natural vegetation management.
OCR for page 42
~ / Oaf TO
Tags ire a soup of ~01 ~iou~ou~t the Gould!. Kilns near l~lhe~s~,~hia, By,
~ ~.
Credit: Douglas Lye.
This can include selectee h.arest of forest products. Con side able
research as been p~de#aken on Me s~sta~ipabIe m.~page~nt of Topic
moist Rests Oberon and Vi~n~nt' 198~ byatt~Sm:i~t~, 1987~/ and it is
tonse~~bon of these forests that is regiving the roost Benson in the
media. Be genes i~pl~i^~tions of Such natural vegetation ~a~gement
systems remain unexplored, cart the population sizes and the stare
of genetic On maintained byth~ose~systems ~ouldun~doubtedl~y
Aged ~evbl~i? of these ^~sys~s.Rea ~ ~ bad Tendon ha
been {yen to the con~se ~ tion of Bees and shrubs in doer zones,
although they maybe the sole sou~=eofs0=ep~lint ma~r~Is,especiall~v
Or ED and fodder. OPen' tag, the day zones contagion tree species thy
could have goat potential as exotic (~non~naJ~e) toes for other argons.
A range of And management systems, including Oral development
Best, aDey fling, am s~vipastoral system am often c~lec~vely
termed agro~rest~. Trees, crops/ and domestic animals are mixed
OCR for page 43
Multiple Uses of Forest Trees / 43
simultaneously or sequentially in such systems to obtain increased and
sustained multiple benefits from limited land resources. In rural devel-
opment forestry, planted trees are used for the benefit of rural com-
munities or individual farmers. Such systems include the small plan-
tations of community and farm woodlots and the establishment of trees
in farmland for shade, shelter, fuelwood, soil improvement, or other
purposes. The selection of source populations and species for these
systems is just beginning.
One of the most widely researched agroforestry systems is alley
farming. This is a term for a form of land use in which one or more
rows of trees are planted alternately with several rows of agricultural
crop plants. The trees in this system are hedged (cut back frequently)
and contribute decomposing leaves (mulch). This practice increases soil
fertility and provides fuelwood as well as other benefits. Despite
considerable research, however, adoption rates for alley farming remain
low.
Silvipastoral systems incorporate tree and shrub management and
animal husbandry. The trees are used for fodder production, shade,
and pasture improvement. The intensity of such operations varies from
extensive range management in dry zones to intensive trees-over-pasture
systems in areas of higher rainfall. The trees may be planted or occur
naturally.
Research on agroforestry systems is increasing and often benefits
from a multidisciplinary approach. Much of the work is being conducted
as part of the research program of the International Council for Research
in Agroforestry. Related research and development work on multipur-
pose trees and agroforestry systems in India and in southwest and
southeast Asia is being conducted as part of the Forestry/Fuelwood
Research Education and Development project coordinated by the For-
estry Research Institute of Malaysia (Plucknett et al., 1990~.
Industrial Plantation Forestry
Industrial plantation forestry is practiced on large areas that are
established and managed intensively, often with exotic species, for the
production of timber to supply sawmills, pulpmills, veneer factories,
chipboard plants, and so on. In developing countries, the plantations
are usually owned and managed by state enterprises, although com-
munity, company, and private ownerships of forests exist in the tropics.
In temperate countries, industrial plantations contain largely conifers
(especially larch, pine, and spruce) or fine hardwoods (ash, beech, and
oak). In tropical and Mediterranean countries, plantations consist of
OCR for page 44
44 I Forest Trees
TABLE 2-3 Growth Rates of Selected Tropical Plantation Tree Species
Yield Rotation
Plantation Development Species (m3ha-'a~~')0 (years)
Scott Paper Co., Costa Rica Pious caribaea 40 8
Aracruz Florestal, Brazil Eucalyptus gratis 35 7
Jari Florestal, Brazil Gmelir~n arborea 35 10
Jari Florestal, Brazil P. caribaea 27 16
Fiji Pine Commission P. caribaea 21 12-15
Seaqaqa plantations, Fiji swiete,Zia macrophylla 14 30
Viphya Pulpwood Project, P. patula 18 16
Malawi
Commonwealth New Guinea Araucaria spp. 20 40
Timbers, Papua New Guinea
Paper Industries Corp. of Albizzia falcatarin 28 10
the Philippines
Shiselweni Forestry, E. gro'~dis 18 9
Swaziland
Usutu Forest, Swaziland P. patula 19 15
n Cubic meters per hectare per annum.
SOURCE: J. Evans. 1982. Plantation Forestry in the Tropics. New York: Oxford University
Press. Reprinted by permission of Oxford University Press.
mainly eucalypts, Gmelina (widely used for timber), mahoganies, pines,
and teak, although many other species have potential for specific
conditions, such as laurel and Leucaena. The area of plantations (both
industrial and those not strictly for industrial purposes) planted in the
tropics totals 1.5 million ha annually with a current cumulative standing
area of approximately 11 million ha.
Growth rates for tropical plantation species are shown in Table 2-3.
By comparison, the mean annual growth of a naturally occurring climax
tropical forest is rarely greater than 3 to 4 m3 per hectare.
Constraints and Opportunities of Land Use Systems
Although managed breeding programs are used in some areas,
intensive forestry on a large scale is possible only in relatively simple
ecosystems. For large-scale but low-intensity management, as for amen-
ity, fuelwood, or protection forests (e.g., windbreaks), only low-cost
breeding and regeneration programs are economically feasible for main-
taining forests or afforesting impoverished landscapes. For small-scale,
low-intensity forestry, as practiced to maintain ecosystems, feasible
management could still include controlling the size and distribution of
OCR for page 45
Multiple Uses of Forest Trees 145
clearings or reproduction patches. For more intensively managed areas
in which large-scale afforestation or reforestation is needed, as in some
tropical areas, the management technology may still require research
and development.
Current investment levels in land use systems are rarely high enough
to duplicate the intensive breeding or conservation procedures used
with agronomic crops, even for species currently used in industrial
forestry. Even if high-genetic gains in productivity can be expected,
investment is generally low. This may be due to the length of time
required for forestry to provide investment returns and for genetic
techniques to influence forest productivity. It may also be due to the
misconception that nonindustrial uses are of limited value. Investors
find little likelihood of immediate profit even though the long-term,
societal benefits may be high.
Research to develop faster breeding techniques and low-cost fores-
tation programs for using selected stocks of many different species could
induce more investment. Even when the economic use and value of
forestlands can be feasibly and substantially enhanced by appropriate
breeding, however, economic inhibitions continue to deter private
sources from developing the genetic resource.
INCREASING THE USEFULNESS OF TREE GENETIC RESOURCES
Given the lack of knowledge about the nature and distribution of
forest genetic resources, substantial efforts are needed in two other
traditional stages of using plant genetic resources: plant exploration and
evaluation. Both are necessary before sustained utilization of the re-
sources can be assured. In addition, efforts should be organized to
coordinate the exploration and evaluation of programs of various
agencies and governments. Finally, programs are needed to test and
conserve species whose potential value is not yet known.
Exploration
For a given species, its natural range must be explored and areas to
which it has been introduced must be identified. Determination of its
taxonomic status (relationship to other species) and study of its natural
breeding system are also essential. Such information is reasonably well
known for most of the temperate-zone species among the 100 tree
species used in commercial plantations. From several hundred to a few
thousand other potentially valuable species, particularly in the tropics,
are not yet widely used either for commercial purposes or for rural
OCR for page 46
: e-
~ :- ~
If ~ ~
ed~na.1 quinine for the treat-
ment of ~malada was od~na~lly
dredged Cam the ~^ of the
age, a ~~^
South eden gin West.
~ U.S, ~ I.
~ a
, .:~s
,.. a,....
.......
development. Li~leis known about ~diratthbsute~s,status, or d~istrL
bubon(~B~rl~ey and van Cbrl~o~i~,1 ~ ).Por~man~y,t~heir~=produrdve
sv~s~m,ro~ulat~nvariab~on,anddistributio~na~ al~solittl~eun~de~rstood.
Exsi~ tieldt~riaiscoup~led With molecu1aror~locbe~mIcalanalysesa~re
needed to deermi~ne the pattern and extent of genetic vadatio~ns far
mangy species. Well~des~i~ned, replicated experiments on an a~rraY of
geld sites provide data on the vadabon among populations in su~~lval,
growth, p~ductiVi~ty/ and qualitative chamct~e~stics. Through preen
finance testing (repeated trials on a range of sites), estimates can be made
off the importance of ge~notype~e~nvironment Infection effects. This in
, , ,
tarn, indi~tes the extent to enrich individual populations should be
conserved sepsa^~Iy and also bred separately in the future. (Details of
the design/ management, and assessment of such trials am given in
Budey and Wood Q976] and, far multipurpose ~es, in Bu~ev and
Mood [1987] ~
OCR for page 47
Multiple Uses of Forest Trees / 47
Coordination
When a species is indigenous to several countries and is useful in
several others, great advantages accrue from organizing coordinated
programs of exploration, collection, and evaluation. Such coordination
would minimize the number of collecting missions and maximize both
the comparability of sampling within the natural range and of testing
in experimental locations. Often such projects have been undertaken
by organizations in developed countries. Examples include the Com-
monwealth Scientific and Industrial Research Organization in Australia
(many eucalypts), Centre Technique Forestier Tropical in France (various
tropical species), the Danish Forest Seed Center (Gmelina, teak, some
tropical pines), and the Oxford Forestry Institute in the United Kingdom
(Central American pines and hardwoods, some Asian tropical pines,
and some indigenous African acacias).
The Food and Agriculture Organization of the United Nations, in a
program for arid-zone species supported in part by the International
Board for Plant Genetic Resources, took a somewhat less centralized
approach by asking research institutions within the natural-range coun-
tries to make collections and pool them for distribution to institutions
interested in evaluating them. In either system, herbarium specimens
are collected for taxonomic study, and preliminary observations of
breeding systems can also be made during the exploratory phase.
Development of Programs for Untested Species
For species that are without clear potential production value and that
are not adequately included within ecosystem reserve areas, no programs
to conserve genetic resources exist. Species that might serve vital
functions for ecosystem productivity, recreation, or other diffuse values,
but that are not included in protected areas, have no constituency to
encourage investment in their management or conservation. The iden-
tification and management of such populations for their genetic resources
have received increasing attention in conservation efforts (Schoenwald-
Cox et al., 1983; Wilson, 1988~.
RECOMMENDATIONS
Industrial production forestry and the other land use systems de-
scribed in this chapter are evolving in response to the changing needs
of people, the environment, and industry. To maintain the widest
OCR for page 48
In As, Farmer tags ~ Spine the to collect resign.
Detective reserves is proposed by same Exerts as ~ AL ~1~ income
produdng resources to-be collected ~hi.~le p~se~i~n~ tams. Cedit~: Fog and
~gd!cult~.re Or~ani.~Lon.
genetic array of options aortae fi~,itis n.ecessa) to understand
and work with the exisdngs ~ care of (e~nedc vain in trees
p~:s~p/~, ~ '~) ~ff,gf~f~s~.
C~oopera~on among natio~ns.or between 3.ati~onal~and inte~rnationa1
pro~g:~msca.~n m.a~kee~fEcie~ntuse~o~fJ~i~.i~ted~n~dsan~d echnica~lcapaci~ties
. .
to promote exp~loraSo~n~and evaluation. Explo~=tison is necessary to
dee~nine file nature and extant of genetic d~e~i~ b~ &~e~ age
.~
species. Data on the ~e-og~p~hic dist~dbudon,taxon~om~y/ biology' and
ecology of a species maybe neededt!osupplemeniLn~o~ledgeo-bta~i~ned
from materialaIreadyin reserves or collechons~ The in~rmabon~athered
through evaluation is crucial for making Rise decisions about Unseating
and using species end populations.
For many s~peciest~hat originate in a country or region where they
may have relatively ~litt~Ie value but may be of maioreco~n~o~.tsig~niEcance
OCR for page 49
Multiple Uses of Forest Trees / 49
elsewhere, three questions are raised: (1) Who should conduct and pay
for exploration and any subsequent in situ conservation? (2) Who should
conduct and pay for testing and establishing ex situ conservation stands?
(3) Should the country of origin restrict export or charge origin fees for
its genetic material? These issues have yet to be raised seriously in
forestry, but they are undergoing major international debate for food
crop species.
Forest genetic resources programs should conserve species that lack clear
present or potential value and those that have known potential value.
Breeding programs that do not rely on expensive testing or lengthy
regeneration techniques should be instituted for a large number of
species, especially those being newly brought into genetic management
programs. For the many hundreds of species of potential value, genetic
surveys and sampling for multiple populations are needed and might
be combined with preliminary breeding operations. Of the species
currently being tested or considered for multiple breeding populations,
such as teak in Thailand (Wellendorf and Kaosa-Ard, 1988), most would
require an increase of 5 to 10 times the current funding. To develop the
species of known potential value, an order-of-magnitude increase in the
number of species included in exploration and testing programs is
needed. To conserve the species that lack clear current or potential
value, additional efforts are needed.
OCR for page 50
Representative terms from entire chapter:
potential value
