Notes
6.2 Wood, Fibre and Energy Production
6.2.1 Expectations for industrial wood production
© FAO 2009. Planted Forests: Uses, Impacts and
Sustainability (ed. J. Evans) 61
6 The Multiple Roles of Planted Forests
J. E
VANSindustrial forest plantations alone supplied 35% of global roundwood in the year 2000 – there is no doubt that production is rapidly shifting away from native forest formations to planted forests, and they will become the principal source of production. This is not a new observation (e.g. Sedjo, 2004; Youngs, 2004), more a new appreciation or understanding. As noted earlier, it completes the domestication and intensifi cation of forest production, reaching what agricul- ture achieved centuries ago.
The estimate of potential yield from planted forests in 2005 in Chapter 5 (1.4 billion m3) is remarkable. It indicates that two-thirds of the world’s industrial roundwood production can come from just 7% of the world’s forests, or a mere 2% of land cover. Incidentally this supports Clark’s (2001) contention of no glo- bal wood shortage. With the investment in genetic tree improvement and realiz- ing the potential of biotechnology (Park, 2002; Sedjo, 2004; Suttonet al., 2004;
van Frankenhuyzen and Beardmore, 2004; Nehraet al., 2005) – always suppos- ing FSC and other certifi cation bodies don’t persist with bans (Strauss et al., 2001) – alongside strategies of concentrating on the best-adapted sites (Fox, 2000) and other aids to improvement, further increases in productivity per hectare are already assured. Further comment is made later about genetic improvement, but Kanowski and Borralho (2004) report 200 tree species subject to one breeding cycle and 60 or so more intensively. Initial improvement yields typically 10%
gain where there is small natural variation and rather more where this is higher.
Examples of forest-scale gains, as opposed to experimental trials, are still limited, but Evans (2005) attributes a 9% improvement in height growth for fourth-rota- tionPinus patula to genetic tree improvement. In the UK genetically improved Picea sitchensis, the principal planted species, has predicted gains of 8–15% in height and over 20% in diameter (Lee, 1999). Rapid capture of such heritable gains through clonal planting is now widely pursued, for example, in Aracruz, Brazil (Campinhos, 1999) (Fig. 6.1). Of course, tree breeding and biotechnology interventions also aim at delivering improvements in disease resistance, wood properties and other benefi ts. Increasing yield per hectare from silvicultural inten- sifi cation is a continuing trend in planted forests for production.
Overall, fi bre supply from planted forests is set to increase dramatically and eliminate any lingering spectre of wood shortage globally, if not always locally.
Not only will the resource of planted forests largely meet current levels of demand for industrial wood, but, in the medium term, surpluses are possible that can make inroads into and substitute use of non-renewable construction materials that are far more energy-intensive – cement, steel and aluminium (Bowyer, 2004). Such surpluses are highly likely if signifi cant investment occurs in carbon afforestation and reforestation as a climate change mitigation strategy. Not only will much virgin wood be grown but, ultimately, its very best use is a win–win, both to substitute for other materials as a renewable, low energy-consuming alternative and in ways that have long in-use life, as do most construction and furniture uses, and so prolong carbon storage. Indeed, consumer preference is beginning to place a premium not only on competitive prices but also on envi- ronmental and social justifi cation in product use. There is every prospect of reversing the trend of the last 50 years, and seeing solid wood and reconstituted wood products regain market share in the construction industry.
Product quality
But questions must be raised: (i) The roundwood supplied from planted forests is much less varied than has hitherto been extracted from native forest. And not all tree species do well when planted; (ii) Wood quality will change because of fast growth rates, proportionally greater juvenile or core wood, possibly less heartwood, shorter lengths of clear timber and poorer fi nishing qualities of solid wood because of wider rings from faster growth; (iii) Log dimensions will generally diminish. The large diameters of ‘old growth’ will give way to smaller sizes, necessitat- ing re-equipping of mills and greater investment into fi nger joints and similar ways of utilizing small-dimension material; (iv) These three trends will be miti- gated by an increase in adoption of re-constituted board and panel products, and by including wood quality parameters in genetic improvement programmes (Lee, 1999; Barbour, 2004); and (v) Fibre supply for pulp will also change, with even less coming from native forest than now (Simula, 2002) and with many changes for the better from advances in technology (Bailey et al., 2004), in par- ticular the uniformity of industrial feedstock that planted forests afford. The industrial resource, based on planted forests, will be different. Offsetting benefi ts include greater security of supply, uniformity of product – species and sizes, and, obliquely, the benefi t of easier certifi cation of planted forests because of demon- strable compliance with regulation standards.
Premium hardwoods
A further question concerns supply of premium hardwoods. In temperate coun- tries long rotations and costly silviculture (Kerr and Evans, 1993; Joyce, 1998) Fig. 6.1. Harvesting of clonal Eucalyptus in Aracruz, Brazil: wide corridors of native forest and protection of riparian zones surround such intensively managed planted stands. (Source: FAO.)
will deter major investment on commercial grounds, though some production will arise from plantings of native hardwoods for purposes such as amenity and biodiversity (Fig. 2.2). In the tropics the picture is bleaker. There are the same issues of long rotation and cost, but also silvicultural problems with the two most important families, namely, shoot borers with most Meliacaea (mahogany) (Evans and Turnbull, 2004) and poor establishment and erratic growth of dipte- rocarps (Weinland, 1998). There is huge potential and opportunities (Salleh Mohd, 2000; Varmola, 2002; Kjaer, 2004), for example with the little-researched genusInga in the neotropics (Pennington, 1997). On the whole, foresters have been content to confi ne interest and focus research on ‘easier’ species to grow industrial rather the cabinet grade timber – with, of course, the well-known exception of teak (Pandey, 2000). There appears no immediate change to this outlook.
Outlook
Planted forests are becoming the world’s industrial feedstock for wood products.
This will require similar inputs as farm crops of high-quality germplasm, site/
species matching and, for forestry, a relatively high intensity of silviculture – establishment, protection, management, harvesting and regeneration. Such for- ests will represent one branch of an emerging dichotomy: that of intensive cropping for industrial end uses in contrast with less intensive management for many non-industrial uses.