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We need intensively managed plantations

Wink Sutton's Blog
Sunday, May 29, 2016

Wood is the world’s only environmentally friendly and sustainable raw material. There are current global proposals for a significant increase in wood use such as in the manufacture of biofuels and plastics to replace the use of fossil fuels. The most exciting proposals are for wood to reduce the need for steel and concrete in the construction of high rise buildings. Wooden buildings of 10, 20 and even 30 stories have been proposed or even started.

When there were few humans on earth we were hunter-gatherers obtaining our food and wood from the natural forest.The human population is now so large that we have no option but to get almost all our food from intensive agriculture. In contrast, we still get most of our wood from natural tree species in indigenous forests of which some are managed. Because plantations of some exotic tree species can be much more productive than natural forests even if managed, then globally more of our wood must be supplied from plantations.

Greenpeace provides an insight into how an environmental organisation regards plantations. Greenpeace’s Forest Campaign Manager, Grant Rosoman, in a paper to the United Nations Forum on Forests Expert’s Meeting on Planted Forests in March 2003, provides an interesting insight into the Greenpeace attitude to plantations and understanding them.

Rosoman restated the Greenpeace position on plantations − ‘Greenpeace doesn’t like plantations. We have learnt to live with them for strategic advantage. We disagree with calling them planted forests because they are not forests ... it is not enough justification for plantations to be considered good if they are simply substituting, on a global basis, supplies from poorly managed or increasingly depleted natural forests.’

Later in the paper Rosoman’s criticisms of plantations include the use of pesticides, timber preservation treatment and monocultures. Plantations are criticised for their lack of species diversity advocating a preference for native species and a range of different species. Greenpeace is opposed to carbon credits for plantations.

Rosoman appears to be unaware of New Zealand’s plantation history, especially why the country moved to obtain most of its wood from plantations. In a disservice to earlier forestry visionaries, Rosoman states ‘The reliance of plantations as a source of the wood and fibre was not a matter of good planning or management but rather a strategy to deal with the failure of the State and New Zealanders to [manage] their native forests in any way for the future wood supply.’

Is Greenpeace implying that most of our wood should come from managed indigenous forest? If so, Greenpeace is in total disagreement with most other New Zealand environmental organisations.The initial advocacy for plantations came from the realisation that New Zealand’s indigenous forest was rapidly being converted to agriculture. The early foresters considered the option of indigenous forest management, but mainly because the forests were slow growing, it was obvious that sustainably managed indigenous forests could not supply most of the wood New Zealanders require.

In addition, managed indigenous forests required management for at least 100 years before there could be any significant wood harvest. The perception around 1900 was that forest clearance was so rapid that exploitable indigenous forest would be exhausted by 1945 to 1950. It is unrealistic to imply that most of our wood could come from responsibly managed indigenous forests. If New Zealand’s four million people only used one cubic metre of wood per person each year, about half our present level of consumption, assuming there were no wood exports and the indigenous forest growth averaged one cubic metre a hectare each year, we would require four million hectares of native forests to be managed for wood production.

Not only is this unthinkable but the wood harvested would be prohibitively expensive for general use. Indigenous timber may be acceptable for furniture or feature panels, but I cannot see the environmental movement ever accepting indigenous timber being used for house construction, building boardwalks, outdoor stairs, fences, chicken coups or for pulping.

Given Greenpeace’s advocacy of responsible indigenous forest management why did they not publicly oppose the Labour government’s politically motivated scrapping of the West Coast Accord which resulted in the demise of West Coast Timberlands? Such action may have brought them in conflict with some other environmental groups but it would be consistent with their basic philosophy.

Although this article challenges Greenpeace, my comments are applicable to most environmental organisations. At least Greenpeace had the courage to present an anti-plantation paper to a meeting that generally regarded plantations as necessary and beneficial. The world has no option but to get more of its future wood needs from intensively managed plantations.

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Introduction to Continuous Cover Forestry

Eric Cairn's Blog
Monday, April 25, 2016

Introduction

The Wellington branch intends to run a series of articles and field days on Continuous Cover Forestry. Government policies, particularly in regard to Permanent Forest Sink Initiatives and in the draft National Environmental Standard for Planation Forestry, are starting to recognise that there are alternatives to clear-fell industrial forestry and the benefits of avoiding clear-fell regimes.

Background

Forest owners are under increasing pressure to join forestry certification schemes in order to retain overseas markets. There is a public perception, rightly or wrongly, that large-scale monoculture forestry, along with huge areas of clear fell at harvest, is not ecologically sensitive. A way to improve public opinion and be more ecologically friendly is to follow the principles of Continuous Cover Forestry (CCF).

CCF means greatly reduced coupe size, mixtures of species and age classes and maintaining or creating habitat and species diversity.

CCF may facilitate:

  • a change to harvesting methods (reduced use of cable haulers),
  • the need for more sophisticated forest management techniques, and
  • different regulatory approaches by national and local authorities.

Definition

There is no internationally recognised definition of CCF, but in my opinion it covers a wide spectrum of forestry activities: almost anything but large scale clear-fell regimes.

In its simplest form, CCF can be a series of small compartments of single age, single species with a different specie in each compartment. Harvest is by felling a mosaic of small coupes, thus minimising negative effects on soil, water quality and wildlife disruption.

More complex forms of CCF use mixed age and/or mixed species tree regimes. At the extreme , CCF systems resemble natural forest. Harvesting is then small coupe or single tree selection and stand management may take the basal area of various size classes into account and limit the numbers of trees in each size class according to reverse J curves. These complex variants are usually much more complicated to manage than single age and single species stands.

Feasibility

While US and European foresters accept CCF as feasible, most NZ trained foresters reject the notion that CCF is either reasonable or profitable, particularly for Pinus radiata or on steeper sites lacking easy access.

Radiata is seen as a commodity product and profit margins are often small. Large- scale operations seem to be the norm, and the costs of logging small stands could be high due to set-up costs. Consequently radiata does not lend itself to CCF. From a harvest cost point of view, there would be advantage in growing higher value species, allowing a better margin to the grower.

In most countries CCF is built around management of indigenous species. In NZ however there are strong disincentives for cultivating native trees as there is no guarantee of a right to harvest and crop rotation times may be very long. Perhaps growing mixtures of exotic and indigenous species will provide high ecological and recreational values and still prove profitable but as yet there is little hard data to support this idea.

Profitability

CCF is suited to high value species, which allow low impact harvesting systems and in some cases on-site milling. While operating costs per tonne are higher than with clear-fell, capital equipment costs can be reduced.

Factors affecting stand profitability include growth rates, saw log values, basal area, economies of harvesting, rotation times, labour of planting, silviculture and management, and appropriate markets for the species and grades obtained. It is hoped that the (potential) higher values of alternative species will offset higher extraction costs and slower growth rates but minor species can be very difficult to market.

Growers contemplating CCF also need to understand whether they want a defined rotation / investment time or the opportunity for a steady income stream over a long period while maintaining a high stand volume.

There may be tax implications here as sale of the forest attracts tax liabilities to both seller and buyer on the assessed value of the stand (cost of bush, see Tree Grower Feb 2005, Murray Downs, on NZFFA website). Amenity trees have different tax liabilities. Sole operators and companies are taxed differently.

Strengths and weaknesses

The Classic European/German system of Plenterwald has the philosophy of leaving the best performing trees until last. This could mean that some oaks would grow for hundreds of years before harvest, but ultimately deliver the highest value and fastest increments to stand volumes. Less scrupulous foresters remove the best performing trees (hi-grade) and leave the rubbish for future generations. This practise rapidly degrades the genetic potential as the poorer trees are left to breed when the higher quality trees are cut.

CCF upside:

  1. the balance of a mixed species stand to be altered mid rotation to meet shifting markets
  2. some very long individual tree rotations to maximise value
  3. a more balanced forest microclimate that might improve the quality of an emerging crop
  4. better outcomes for water, soil and ecology
  5. better outcomes for recreation and amenity
  6. an uneven height canopy that is said to reduce pressure harmonics and reduces the risk of wind-throw
  7. profitable management of small scale blocks with dedicated and specialised labour input i.e. farm forestry.

CCF downside:

  1. there is a limited availability of improved genetics of alternative species in NZ
  2. need for sophisticated knowledge to manage stand volumes according to species and age structure.
  3. need for care when thinning or harvesting to avoid damaging other crop trees
  4. coupe size may depend on shade tolerance of the species, and potential for weed infestation
  5. thinnings and low grade trees possibly not marketable except as firewood or round wood
  6. mature logs of minor species might be difficult to sell
  7. limited opportunities for economies of scale in harvesting and marketing
  8. higher risk of wind-throw or snow damage for tender advance regeneration understorey
  9. need for good road access and tracking to minimise extraction costs.

In practice

In New Zealand we have so much to choose from, but little experience to draw on (except for indigenous forests). But why follow the North American or European recipes when other species might provide a better return for NZ sites?

The key steps are:

  1. Firstly, decide whether to grow single age stands or mixed age and or mixed species stands.
  2. Start with pioneer species and plant tender, shade tolerant ones later if required.
  3. Match your timber species with climate, soils and exposure and mycorrhiza, remembering that eventually the forest will provide shelter for regenerating trees.

Choices

Cypresses, Douglas fir, redwoods and cryptomeria are moderately shade tolerant. Stands with these species can have high basal areas. There are probable markets for medium diameter thinnings of these species.

Acacia melanoxylon benefits from competition when young but must be opened up to wide spacing by 10-15 years or else it will lose volume in low value upper branches and growth will slow. Small diameter blackwood (and most small eucalypt) is full of tension and is difficult to saw into straight boards. Thinnings therefore have little value as sawlogs, but if durable species are grown, sawn or round wood may be in demand for vineyard posts. (e.g. some stringybark eucs).

As hardwoods generally need even growth and wide final spacings, consider an understorey of shade tolerant species as an advance regeneration succession crop. There is a lot of light under a eucalypt stand, especially when thinned correctly. Why not under-plant with a succession crop of native trees? Kauri, puriri and totara could do well and be drawn up in light wells. Obviously under-plantings need to be arranged with harvest of large piece size in mind, perhaps strip planted away from harvest lanes.

Hardwoods such as acacia, oaks, elms, ash, walnut and chestnut benefit from a sheltered environment, but would need to be well spaced by mid rotation. These species are suited to a park like environment, or under-grazed with selected livestock.

Poplars could be a very useful nurse crop and are well suited to pastoral systems.

Light-demanding species such as radiata, can still establish in light wells. The growth may not be as fast initially as open grown stock. In the experience of John Wardle, selection harvesting of pine ensures that most stems harvested are at premium quality and the mean annual increment for the whole stand is higher than a conventional stand. (A conventional stand means annual increment is very low when the stand is young. The slow growing understorey trees are like advanced regeneration in a shelter wood system.)

Some species require soil disturbance or “mineral soil” for self-regeneration. Soil disturbance is often a by-product of selective harvesting, but the species ecology needs to be understood for successful self-regeneration. The tradition in NZ is to replant with improved selections of target species.

Case studies:

Later articles will feature case studies from around NZ and perhaps elsewhere. I understand that John Wardle will shortly publish a book on his CCF experience with black beech and radiata pine. Ian Barton, Paul Millen and those managing native forest stands also practise CCF. Ian Barton through Tanes Teee Trust published a booklet on CCF in 2008.

Disclaimer: Personal views expressed in this blog are those of the writers and do not necessarily represent those of the NZ Farm Forestry Association.

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