1 June 2016
These days plantations for timber are viewed unfavourably by many conservation minded people. This is unfortunate because timber plantations can have multiple benefits depending on how they are managed. My mission here is to outline the process of establishing and maintaining a plantation from conception to a time further away in years towards either final harvest or partial harvest, or no harvest at all; in other words in the event that the owners prefer to keep the plantation as an amenity planting for enjoyment.
I tend to refer to these timber plantations as Environmental Woodlots because despite an intended end use of harvest for timber, these plantations provide multiple environmental benefits for as long as they are standing and managed. I anticipate that people who might be interested in establishing and managing a woodlot for future timber harvest might already be wanting to do their bit for the planet in helping to mitigate a range of environmental issues in today’s world.Planning
The first step in getting a plantation project off the ground is the helping of the potential client to identify what they really want from the project. That way planning can be done with the clients needs foremost in the thinking. Ideally planning begins a year before planting time so that there is time to cover all the issues involved with planning. ( Does the client already own land or do they need help sourcing suitable land?)
If the client has land, planning would ideally start in June July, August of the year before planting.Soil Pits and soil tests, Rainfall.
Soil pits should be dug to ascertain the depth of soil to bedrock and also the soil profile. This helps with selection of suitable species. Soil specs and rainfall combine to provide a basis for species selection.
The information from the soil pits and tests will give the potential owner enough to decide whether or not to proceed with a project.Cost income projections.
Cost income projections can be done in the form of a spreadsheet to give a financial basis for the potential project. This can also give the potential owner confidence of the processes and costs for the life of the project, year by year.Soil preparation.
Depending on the soil test results lime and fertiliser applications are made before deep ripping by bulldozer. The ripping is done to a minimum depth of 600mm or 60cm and the ripper must have a wing on it to lift and shatter the soil as it passes through the soil.
Ripping is usually done in the driest months, December to March so that maximum shatter is induced in the soil profile. This shatter is what loosens the soil to allow the roots of the young seedling to follow the moisture as it recedes in to the summer as the ground heats up.
Where soil is particularly cloddy with large hard lumps of soil and lots of air gaps we usually disc the ripped mound to till the soil more ready for planting and reduce the large air gaps.Pre-plant weed control.
Usually one month before planting time ( June for pine, July / August for eucalypts ) pre-plant weed control spray is applied to a one metre wide strip along the mound to knock down any live weeds and prevent germination of new weeds. This spray gives about six months of no weed competition for the young seedlings from planting time.Planting.
Planting is done in the mid winter for pines ( when the seedling is dormant ) and spring time for eucalypts when the seedling is on the move and the soil is still moist but starting to warm up.
June / July for pines. September for eucalypts.Second year weed control.
By the onset of autumn and winter following planting sometimes the weed / grass growth has been vigorous when the preplant weed control effects wear off and if the weeds and grass are not controlled they will seriously affect growth in the seedlings into the second spring if left unchecked.
Generally if seedlings are more than 1.5 metres high in the first year from planting and there is a lot of grass and weeds present then second year control is considered not necessary. If the seedlings remain at say half a metre high then second year weed control is called for.Foliage sampling.
Foliage sampling can be a good way of determining nutrient status of young seedlings and can indicate that application of fertiliser may be called for. This is done in June when seedlings are at their most dormant.
Monitoring of plant health and nutrient status is the main observation until time for the first prune, usually year five in pines and year three in eucs.Pruning and thinning.
Pruning of the best 30% of trees is designed to produce clearwood in the bottom 6 metres of log. By removing the branches the tree grows knot free timber so that in an ideal situation the bottom log is defect and branch free and of high value. The pruning is usually done in three lifts of approximately 2 metres per lift as the tree grows so that removal of the bottom 2 metres of branches does not slow the growth of the tree too much.
Rule of thumb; pruning starts when the tree is at least 5 or 6 metres high and pruning the bottom 2m – 2.5 metres would remove less than 50% of the green crown.
With eucalypts the first prune can begin as early as age three and with pines as early as age five or six.
Thinning to waste (Non commercial thinning).
Thinning progressively gives the crop trees room to grow diameter. By removing the worst trees and retaining the best trees the plantation is managed for eventual harvest of the best trees. Initial thinning in eucalypts is to waste where the first thinning rots on the ground because the trees are too small to be of commercial value.Commercial Thinning.
More trees than are required for final harvest are planted and in the case of clearwood pruned regimes, the thinning removes the worst trees first. This is managing the genetic variation that exists in seed produced tree seedlings. Ultimately with eucalypts approximately 30% of the planted stock end up being pruned as an interim crop, 50% being retained until say age 8 when the 20%of unpruned retained stems are thinned for pulpwood commercially, with 15% or less being the ultimate final crop figure depending on desired final diameters.
For volume based forestry, ( pines in most cases in Australia ) the focus is on optimising volumes produced for lower grade material such as pulpwood with thinning being done commercially and progressively from about age 13 through to leaving a final crop of sawlogs at age 35 years plus. This regime ensures that branch size is kept small enough that knot size in the timber is small enough that the timber is suitable for construction grade wood for structural use.
One needs to be aware that thinning opens up the stand and can make it vulnerable to wind throw if high winds are experienced soon after thinning if the ground is still soft from say winter or spring rains.
Pines usually have up to four commercial thins before final harvest. The first thin is cost neutral because of small piece size and lower volumes of wood being removed. After the first thinning all thinning usually produces an income, increasing at each thin according to piece size and volumes being removed. The larger the piece size, the more commercially viable it is especially where sawlogs are concerned.
Eucalypts may have as many as three commercial thinnings before final harvest at age approximately 20 to 25 years of age. The first commercial thin at about ge 8 produces mainly pulpwood but subsequent thins may produce sawlogs and peelers for plywood.
In one of my joint venture plantations the first commercial thin was at age five ( shining gum ) and whilst the return was very small it did better than cost neutral.Monitoring the crop from first thin through to final harvest.
The role of the plantation manager / forester from the time thinning starts is to monitor tree growth and schedule subsequent thins so that the crop tree growth is fast and even. The idea is to maintain even growth and consistency in the growth rings so that the sawlogs are more stable at milling time. This is particularly important with eucalypts ( hardwood ). Pine ( softwood ) is less demanding in this respect.
Other aspects to managing a woodlot for multi use and benefits.
I favour the planting of native understory shrubs either in a perimeter belt or randomly throughout the plantation to provide biodiversity to what might otherwise be a monoculture. In the case of eucalypt plantations this makes the plantation more of a natural forest with a balance of plant species for native wildlife, bees and soil benefits. For instance wattles fix nitrogen in the soil and are symbiotic with eucalypts and they provide food for small mammals such as gliders and possums, and pollen for bees.Shelter for farm animals.
Strategically placed plantations can provide shade from the hot sun for farm animals, and shelter from cold winter winds. They can also provide native wildlife corridors to allow movement of native animals across the landscape.
A well managed woodlot or plantation can provide a beautiful amenity in the landscape. A place to rest, enjoy the trees, and relax from pressures of life.Shelter and shade for people.
Homesteads and farm buildings can benefit from shade and shelter from thoughtful placement of woodlots in relation to prevailing winds, sun, and buildings where people live and work.Biodiversity for birds, native animals and soil flora.
Planting of belts or random plantings of native understory shrubs is encouraged when establishing woodlots for timber. This increases the environmental component without compromising the growth of the timber trees. This benefits the native birds and animals, particularly the small mammals, and also the soil. Wattles fix nitrogen for instance and they can perform very good work in the soil even when short lived species.
There is a threat worldwide to the bee population. Bees are vital for pollination of a range of crops for food and there is a growing awareness of the need to nurture bees in order to benefit mankind simply from a food supply perspective. Environmental woodlots have the capacity to support bees and having a diverse range of species within the woodlot can enhance the length of time that woodlot can sustain a hive before the bees have to range further afield for food (pollen and nectar).Wildlife habitat.
Environmental woodlots can sustain a range of native animals and small mammals and the value of this aspect should not be underestimated. For instance owls need small mammals to feed on. Small mammals like to live in Eucalypt plantations but feed on wattles so the understorey is important to sustain life.
Value Propositions for Environmental Woodlots;
- Great for the planet – good for the environment
- Enjoyable and enhances quality of lifestyle
- Leave a legacy for the next generation (children)
- Commercially viable investment
- We do the total management package.