Introduction
Planning is an exercise in risk management. Without a considered approach to investment the chances of mistakes are considerably increased.

Correctly sited and managed trees of an appropriate species can enhance the farm, the farming business and the local community in a number of ways (see Understanding Trees on Farms). An inappropriate species, poorly sited and poorly managed, can be a liability.

Objectives, resources and constraints
Understanding the objectives of a block of trees, the resources required to manage the stand, and any constraints, that may limit management options, is an important first step in planning a forestry planting.

The objectives may be as diverse as shelter or bee habitat. A block will usually produce a number of outputs, but the management of a stand should always reflect the most important objectives of the stand, as well as the available resources of capital, labour, and particularly expertise.

For example, a stand that is managed for a principal objective of erosion control, with an important secondary objective of timber revenues, should not necessarily be managed in the same way as a stand grown to maximise return on investment. An investment stand will usually demand greater inputs of capital and labour (including expertise). It may also be more demanding of site quality. A soil conservation planting need not be intensively managed, and would probably have a longer optimum rotation.

Stand management can very from intensive multiple thinnings and multiple pruning lifts with low stockings and short rotations at one extreme to possibly only one thinning, reasonably high stocking with a longer rotation on the other.

Each has its place depending on the objectives and resources of the land owner.

Site selection
Trees should be planted on farms to complement the agricultural outputs of the land. Choice of areas for planting should consider the following.

Identify unsustainable areas.
Many farms in New Zealand are practising unsustainable land use on certain areas. In many cases the practice continues because the situation hasn't reached a crisis point. this does not mean a crisis will not eventually occur.

If a land practice is unsustainable, the problem is immediate. Delays in changing the land use simply erode the productive potential of the land; an example of "reverse development". Does the net return continue to decline despite consistent or increasing inputs into fertiliser, weed control etc?

Identify and avoid critical grazing areas
Siting major forestry plantings on areas that are strategically important grazing areas represents a competitive land use rather than a complementary one. There is little point in planting trees to eventually get the farm into a secure financial position, if, in the meantime, the farm business becomes substantially less secure.

Identify poorly utilised areas
These lower carrying capacity areas are often on steeper slopes or with unimproved pasture. These areas can be considerably more productive in trees while saving some farm costs (e.g. weed control and fertiliser), and improving the utilisation of the remainder of the paddock.

Identify areas requiring shelter and shade. Identify and avoid wilding takeoff sites for spread prone species.

Either with mustering, or disproportionately high stock losses.

Plant gullies, toe and scarp slopes

These sites are often poorly utilised by stock and are generally more suited to trees.

Ensure that scale, access and location of the planted sites is suitable for economic forestry.

Tree growth compared with grass
There is a strong relationship between rainfall and tree growth in the high country. Of the soil factors influencing land use, trees are more dependent on soil depth with adequate soil moisture, while grass growth is more closely related to topsoil fertility and soil moisture. If you provide trees with deep free-draining, but not necessarily high fertility soils, with adequate moisture, some shelter, a warm day temperature and a cold night temperature to reduce respiration of carbon fixed during the day, growth will be excellent. Toe slopes of hills are classic tree growing sites, but not necessarily the best grass growing country. Those often occur on highly utilised tops where soil fertility and grass quality is maintained.

Forest economics
The money eventually returned to the grower from a stand of trees is derived from a sale value per tonne or cubic metre at the wharf or mill door, less a harvesting and marketing commission, transport, roading and log and load costs. As an example, a Douglas fir log sold or $100/m³ at a wharf, with an 8% commission on sale, a transport distance of 120 kilometres at $0.18/m³/km, and a harvesting cost including roading of $14/m³ will return $56.40 to the grower before tax. This is termed the "value on stump" or "stumpage". Stumpage can be in $/m³, $/tonne (very similar to a m³), or $/ha. Because of the "derived" nature of stumpage, location from mill, on-farm access to road ends, scale and the mill door value of log material have important implications on eventual grower returns. Any additional costs involved in extraction, or log values at point of sale, directly effect stumpage returns.

Species choice
In most cases the site characteristics will limit the species options available. The predominant species for the high country will be Corsican pine (Pinus nigra) for the dry areas, and Douglas fir (Pseudotsuga menziesii) for wetter areas. However, where sites are suitable and objectives and resources allow, a wider variety of conifer and broadleaf species (e.g. oak, ash, larch, cherries, acacias, eucalypts, etc) become options.

References
Jackson D S (1972) "Soil factors that should influence allocations of land for forestry or agriculture". Delivered at 12th NZ Science Congress: Section (E5).