Forest Operations > Plan and Preapare for Operations

Plan and Prepare for Operations

Tree Pruning

Some forest growers may decide to prune their trees and pruning is mainly performed on stands of pine trees and the Blue Gums. Native trees don’t need this process.

The advantages of pruning boundary trees in a coupe can be:

• To give safer and easier access for earth moving equipment, building roads and log landing construction, and for log trucks and forest machines to be able to move about safely.
• To improve the quality of the boundary trees, as these trees have more and thicker branches than internal trees.

Figs 8a Before pruning	8b Butt pruning of trees pine	8c Approximately 17 years later

Roading and log landing dumps

This work will depend on the type of terrain the trees are growing on.

Dry stable terrain will not need as much or if any road works at all whereas very wet terrain will need road work done to allow access to the coupe. This work is best completed in the early stages of tree growth.

Marking the coupe

When a stand of pine trees reaches about twelve years of age and depending on their growth rate, the first thinning stage will begin.

Before any trees are cut down, a team of workers will professionally class the coupe for the trees that are required to be harvested and processed.

This process may involve the complete removal of every fifth row, and selected poor quality trees from the two rows either side of the fifth row.

The fifth row that has been cut completely out is referred to as an Out-row or the gullet-row. This row allows the forest machines to access and perform their work. In many blue gum plantations the current harvesting process is clear fell and in this situation there may only be marking of specific areas not individual trees.

What is thinning?

Thinning is carried out mainly in pine plantations as the objective is to grow sawlog.

Trees compete for light, moisture, and nutrients. If they become too crowded, growth slows then they can become prone to insects, diseases and wildfires and may eventually die.

"Thinning" are cuttings made to young trees to help with growth, health, yield and profitability of the remaining trees.

Why thin?

A particular site can only support so many trees per acre.

Foresters recommend planting more trees than can mature on an acre with the expectation that thinning will be conducted when the trees begin to compete for nutrients, sunlight, water and other resources.

Thinning helps the growth potential of the stand, to the trees of highest quality, and favours their quick growth.

Thinning removes trees most likely to die from competition, insects, or diseases and reduces the potential for losses from wildfires.

From an economic point, thinning also makes good sense. By promoting strong growth it reduces the time required to grow trees from low value pulpwood to higher value poles or sawlog.

Commercial thinning provides the landowner with an intermediate return on his/her investment as trees most likely to die before maturing are harvested and sold.

When to thin?

The first thinning in particular should be dictated by forest health considerations and be conducted to maintain strong growth.

Plantations grown in good soils will grow faster and be ready to thin at an earlier age than plantations in poor soils.

Trees grown on a good site will produce sawlog and be ready for harvest at a younger age following three or four thinnings.

How to thin?

Very carefully, as a machine operator you must not thin any trees that are to remain standing in the forest.

Trees that are damaged or have missing bark should be removed during the thinning operation.

If left in the stand, these damaged trees are targets for bark beetles and other diseases.

To prepare for thinning a forester marks every tree to be kept in the plantation, leaving the poorly formed or diseased trees unmarked to be removed.

Plantation foresters will most often recommend a row thinning, where a harvester operator removes every 5th row called a gullet row or out row.

This provides access for harvesting machines to thin within the rows which are left.

The operator will need to thin two rows deep from each side of every access row to achieve an evenly spaced thinning removing all crooked, forked and diseased trees as they work the harvester along.

Usually only chip / pulp, post and rails are processed from first thinning pine plantations.

In row thinning operations the forester marks the trees to remove.

Many foresters recommend this method because only 20 percent of the potential crop trees are eliminated with removal of every 5th row.

A greater number of unwanted trees can then be removed from the tow rows each side of the 5th row giving a good thinning program.

If the stand of first thinning pines trees are of good quality, the forest owner may require the bottom of the better trees to be processed into saw-log. The rest of the tree processed into posts and rails, chip and pulp.

Fig 9 Product cuts out of a soft wood tree

Log cuts for Thinning Operations

1st thinnings

1st thinnings cuts are usually posts and rails, small amount of saw log from good quality trees and chip or pulp log.

2nd thinnings

2nd thinning cuts are usually a significant amount of saw log and chip or pulp log, and may also produce post/rails.

3rd thinnings

These cuts are usually multiple types of saw log classed into length, diameter and quality depending on the quality of the forest.

Clear fall

Everything is cut down and processed and the cuts are usually the first log from the larger, better trees and are high quality sawlogs. 

There could be up to four or more classes of saw logs and chip log from the waste and poor quality trees.