Stand Improvement / Partial Harvest

 

This program is designed to address areas which may need a sound silviculture intervention, but there may not be funding and/or a program available to the landowner.  It is also to continue good forest management practices on private woodlots.  This may entail a harvesting activity (such as, salvage cutting, single tree selection, group selection, sanitation cuts, liberation cuts, etc.) or an intermediate cutting (in which there would be no merchantable wood harvested for revenue) to improve for future merchantable timber and private forests.

 

Selection harvesting or shelterwood cutting, as it is more accurately called, is the partial  harvest of a good quality mature softwood or tolerant hardwood stand with the objective of  promoting natural regeneration.  The normal practice is to harvest the stand in two or more steps removing the lower quality trees first and leaving the best trees as a seed source.  In the past it was common for woodlot owners to harvest in this way but they often only cut the good quality trees leaving the poor trees to be the seed source for the new crop.  This practice came to be known as Ahigh grading@ and is the reason why many woodlots have decreased in quality over the past 200 years.  Today the same harvesting techniques can be used to insure trees of better quality after each harvest, reversing the process of degradation.

 

In order to be a candidate for shelterwood harvesting the trees must be of good quality and wind firm with crown closure being such that it is causing low light conditions on the forest floor; most species will not regenerate under low light conditions.  No more than 30 to 40 percent of the basal area of the initial stand should be removed in the first harvest operation. This will open up the stand enough to allow the light to penetrate to the forest floor but the stand will not be open enough to create blow down problems.  Once the regeneration has been established, the remaining trees in the stand may be harvested.  Care must be taken to avoid excessive damage to the regeneration when harvesting the mature trees.  Of course it is impossible to prevent all damage but if the first part of the harvest has been successful, more seedlings than necessary have been established and thinning will be required in any event. 

 

Nature often supplies us with what we call a two-storey stand, not unlike the results we achieve with a shelterwood cut; a mature overstory with an immature understory.  In order to qualify for a release cut, the understory trees must be young and healthy enough to respond to the release, and must have a minimum average height of 1.25 metres  (4 ft) or more and have a minimum stocking of 75%. As with the second stage of a selection harvest, the damage to the understory trees must be kept to a minimum.  All marketable trees must be harvested and all non-marketable trees in the overstory must be cut and laid close to the ground, not left leaning against the understory crop trees.