34 Short-rotation forestry – a complement to “conventional” forestry .%JTKUVGTUUQPCPF-8GTOC *KIJFGPUKV[UWUVCKPCDNG ack of wood is common in many and abiotic damage. Short-rotation for- RNCPVCVKQPUQHHCUVITQYKPI countries – particularly for forest estry excludes as many of these limit- VTGGURGEKGUUJQYRQVGPVKCN Lindustries in developed countries ing factors as possible. Irrigation and HQTFGXGNQRGFCPFFGXGNQRKPI and for fuel in developing countries. fertilization are often used, but only in EQWPVTKGUCNKMG Greater attention to short-rotation for- an ecologically and economically sound estry on agricultural land and on fertile way. Plantations are weeded and com- forest soils could offer a way to pro- peting tree species are removed. Spe- vide forest industries with enough wood cies, provenances and clones with high resources and people in the developing water-use efficiency or high resistance world with enough fuel, while conserving to frost, insects, fungi and bacteria are natural forests (Christersson, 2005). planted. Fencing prevents browsing by Short-rotation forestry is defined in animals. Plantations are harvested when this article as the silvicultural practice the yearly growth rate no longer exceeds under which high-density, sustainable the mean annual increment. plantations of fast-growing tree species The present article summarizes observa- produce woody biomass on agricultural tions made at a session on “Wood produc- land or on fertile but degraded forest tion in agroforestry and in short-rotation land. Trees are grown either as single forestry systems – synergies for rural stems or as coppice systems, with a rota- development” at the XXII International tion period of less than 30 years and with Union of Forest Research Organizations an annual woody production of at least 10 (IUFRO) World Conference in Brisbane, tonnes of dry matter or 25 m3 per hectare. Australia, in August 2005. It describes The practice should optimize the use of cases in which as many limiting factors as natural resources, environmentally and possible are taken away to achieve maxi- economically, through the application mum growth rate of trees, demonstrating of biological, physical, theoretical and the potential of the practice. Examples practical knowledge (Landsberg GVCN, include poplar in the United States, Can- 1997). The biomass produced is used ada and India, willows in Sweden, bamboo for construction, pulp and paper, fodder in China and Ethiopia and eucalypts in and energy. Wood from short-rotation Australia and Brazil. Examples from some forestry may replace wood from tropical other countries recognize further oppor- forests and from protected forest areas tunities for short-rotation forestry. and thus help conserve valuable natural forests for future generations. ':#/2.'5(41/&'8'.12'& In what is considered “conventional” %17064+'5 forestry in the northern hemisphere, the *[DTKFRQRNCTRNCPVCVKQPUKP0QTVJ entire growth potential of a tree species #OGTKEC Lars Christersson is in the Department of Short is not fully utilized for various reasons: The outstanding growth potential of Rotation Forestry, Faculty of Forestry, Swedish economic and ecological difficulties in 2QRWNWU VTKEJQECTRC and 2QRWNWU University of Agricultural Sciences (SLU), Uppsala, Sweden. creating optimal water and nutrient con- FGNVQKFGU has been realized in Canada -CTVCT8GTOC works in the College of Forestry, ditions; competition from herbaceous and the United States by growing to Dr Y.S. Parmar University of Horticulture and plants and other tree species; and biotic some extent the pure species, but mostly Forestry, Nauni, Solan, Himachal Pradesh, India. 7PCU[NXCVol. 57, 2006 35 In Australia, short-rotation forestry could be used to lower elevated saline ground-water levels, which frustrate the cultivation of all types of vegetation forestry to replace fossil fuels included the existence of well-developed district heating systems in almost all towns and villages and the already widespread use of wood energy (up to 20 percent of all L. CHRISTERSSON energy) in Sweden. Other driving forces hybrids of the two (Dickmann GVCN, ments with plantations of 'WECN[RVWU included overproduction in agriculture, 2001). Hybrids of other poplar spe- species carefully selected for rapid which made land available for forest cies from Europe and Japan have also growth, irrigated with effluent waste- plantations, the high cost of imported been introduced (Steenackers, 1990). water from towns and industries, annual oil and gas, and concern about the green- In Canada and the United States, com- production of up to 40 tonnes of dry house effect of CO2 emissions resulting mercial establishment of poplar plan- matter per hectare has been reported in from combustion of fossil fuels. tations began for the most part in the southeastern Australia (Baker, Duncan In this type of silviculture, 20 cm 5CNKZ 1980s. Spacing varies from 2 × 2 to and Stackpole, 2005). cuttings are planted on agricultural land 3×3m and rotation time from six to In many sites in southwestern Australia, in a double-rowed coppice system, with seven years. Most of the plantations are the saline ground-water table had become repeated harvests after two to four years located in the provinces of Alberta and elevated through replacement of forest (Verwijst, 2001). There are 16 000 ha of British Columbia in Canada and in the with agricultural crops. Strips of care- energy forestry plantations in Sweden Mississippi River Valley and the state of fully selected, deep-rooted, salt-tolerant, today, but based on the overproduction in Washington in the United States. Annual fast-growing 'WECN[RVWU spp., with spa- agriculture and the government’s goal to production reaches 10 to 15 tonnes per cing of 6 to 10 m in rows 50 to 100 m make Sweden independent of imported hectare (Stanton GVCN, 2002). Even in apart, have been planted on agricultural oil, the potential could be estimated at the semi-desert near the Columbia River, land to lower the ground-water table 500 000 to 1 million hectares. irrigated and fertilized hybrid poplars enough for successful agriculture (Wildy Single-stem plantations of introduced achieve an annual production of 15 to 20 GVCN, 2000). The total above-ground 2QRWNWUVTKEJQECTRC and 2FGNVQKFGU and tonnes per hectare (Heilman and Stettler, biomass production, including leaves, hybrids of these have also achieved large 1985). Initially poplar wood was used for is about 10 tonnes per hectare annually woody biomass production (Karacic, paper and pulp, but in some plantations, and is used in the production of charcoal Verwijst and Weih, 2003; Christersson, wider spacing and longer rotations are powder, eucalyptus oil and energy. 2006). Only a few hundred hectares used (sometimes in conjunction with have been planted, but the results are thinning), and some companies now use 'PGTI[HQTGUVT[KP5YGFGP so impressive that many farmers are it for timber, wall panelling, fruit boxes Energy forestry – short rotation planta- showing an interest in planting more. and furniture. tions of carefully selected 5CNKZ species The wood will be used for paper as well and hybrids in coppice systems for pro- as energy. +TTKICVGFEucalyptusRNCPVCVKQPUKP duction of biomass for energy production Utilization of short-rotation forests Australia – was developed in Sweden after the oil as vegetation filters for waste prod- In the homeland of the genus, irrigated crises in 1973 and 1979 (Sirén GVCN, ucts is strongly supported in Sweden plantations of 'WECN[RVWU species have 1983). Factors that enabled the successful (Perttu and Obarska-Pempkowiak, 1998; shown real growth potential. In experi- introduction of this type of short-rotation Dimitriou and Aronsson, 2004).Waste 7PCU[NXCVol. 57, 2006 36 Salix viminalis energy plantation in Sweden, with one-year-old shoots on four-year-old roots reach 30 to 40 tonnes of dry matter per hectare at different rotations (Scurlock, Dayton and Hames, 2000). Organic and inorganic fertilizers are used systemati- cally. Commonly used organic fertilizers are compost, human waste and barnyard manure. These are applied at the rate L. CHRISTERSSON of 1.5 to 4 tonnes per hectare per year, water and sewage sludge, which contain spp. are producing about 300 to 350 m3 buried in 5 to 10 cm-deep channels large amounts of nitrogen and phospho- per hectare in seven years. On the best between the bamboo plants (MOST, rus, are used to fertilize and irrigate soils in this area, without irrigation, INBAR and INFORTRACE, 2002). plantations of willows and poplars. The annual production of 60 to 90 m3 per hec- waste products can also contain pollut- tare has been reported. Despite annual 9QQFRTQFWEVKQPCITQHQTGUVT[CPF ing heavy metals, which some willow precipitation of 1 300 to 1 400 mm, UKVGCOGNKQTCVKQPKP+PFKC clones are able to absorb efficiently. experiments have shown that irrigation As a result of restrictions on felling in nat- When wood from this type of plantation with effluents from communities and ural forests imposed by the Indian Gov- is burned, heavy metals can be extracted industry can double production. Most ernment, fast-growing, short-rotation from the fly ash and bottom ash. How- of the Aracruz plantations are on later- ever, this process is not yet economical, ite soils, and all such forest plantations so today most of the ashes are deposited are limed with dolomite and calcium Seven-year-old Eucalyptus plantation at city waste disposal sites. carbonate and fertilized, particularly in Brazil, ready for harvesting; research