Shelterwood
Yellow birch regeneration, 25 years old
The shelterwood system comprises the replacement of the entire stand in a series of partial harvests in a short period of time compared to the actual rotation length. A series of harvests will remove the overstorey once acceptable regeneration has become established. This system is used in white and red pine as well as yellow birch, red oak, basswood and white ash. Tree species with an intermediate tolerance to shade require full sun after establishment to become part of the next stand.
The shelterwood system can be implemented using small groups, strips or uniformly throughout the stand. I will first discuss uniform shelterwood that is frequently used in white and red pine stands.
Uniform Shelterwood
A series of partial harvests intended on removing the existing forest and replacing with a new forest. A minimum of two, frequently three or four harvests with specific goals to be achieved with each harvest. The initial harvest (preparation cut) will focus on retaining high quality trees while removing inferior stems. Mast and cavity trees will always be retained in each step.
The preparation cut is scheduled when the stand is between 60 to 80 years of age with focus on crown spacing. At this stage the crown widths are often 5-8 m. Therefore after harvest there should be 5-8 m of space between the crowns. Existing regeneration should be protected when possible. It is important to retain dominant trees with well developed symmetrical crowns. Try to retain as much red pine as possible.
The regeneration cut is designed to encourage natural regeneration. The timing of this harvest is during a good seed year, typically 20 years after the prep cut. Crown closure of 50% is the target, frequently 1/2 crown spacing. The crowns of the retained trees are much larger as they have had 20 years of unimpeded growth. Retain healthy, dominant trees with well developed symmetrical crowns. Retain mast trees and cavity trees. Light site prep to expose mineral soil will increase the chance of regeneration becoming established tenfold.
Removal cuts are scheduled after successful establishment of regeneration. Before this harvest(s) can occur regeneration maybe supplemented with seedlings and competing vegetation may require control. Two removal harvests maybe required to establish regeneration and to retain large pine on the landscape. Laying out of skid trails is beneficial before harvest to protect regeneration and to aid the operator in extraction of the trees. The final harvest will leave 25 trees per hectare that are greater than 25 cms dbh. This simulates the result of a catasrophic natural event including fire or severe winds.
The shelterwood system can be implemented using small groups, strips or uniformly throughout the stand. I will first discuss uniform shelterwood that is frequently used in white and red pine stands.
Uniform Shelterwood
A series of partial harvests intended on removing the existing forest and replacing with a new forest. A minimum of two, frequently three or four harvests with specific goals to be achieved with each harvest. The initial harvest (preparation cut) will focus on retaining high quality trees while removing inferior stems. Mast and cavity trees will always be retained in each step.
The preparation cut is scheduled when the stand is between 60 to 80 years of age with focus on crown spacing. At this stage the crown widths are often 5-8 m. Therefore after harvest there should be 5-8 m of space between the crowns. Existing regeneration should be protected when possible. It is important to retain dominant trees with well developed symmetrical crowns. Try to retain as much red pine as possible.
The regeneration cut is designed to encourage natural regeneration. The timing of this harvest is during a good seed year, typically 20 years after the prep cut. Crown closure of 50% is the target, frequently 1/2 crown spacing. The crowns of the retained trees are much larger as they have had 20 years of unimpeded growth. Retain healthy, dominant trees with well developed symmetrical crowns. Retain mast trees and cavity trees. Light site prep to expose mineral soil will increase the chance of regeneration becoming established tenfold.
Removal cuts are scheduled after successful establishment of regeneration. Before this harvest(s) can occur regeneration maybe supplemented with seedlings and competing vegetation may require control. Two removal harvests maybe required to establish regeneration and to retain large pine on the landscape. Laying out of skid trails is beneficial before harvest to protect regeneration and to aid the operator in extraction of the trees. The final harvest will leave 25 trees per hectare that are greater than 25 cms dbh. This simulates the result of a catasrophic natural event including fire or severe winds.
White pine marking, 80-100 year old stand
Strip Cuts
To effectively manage eastern white cedar while keeping harvesting damage to a minimum an even aged system is used. Basal areas (density of trees) of cedar forests are quite high, 40 m2/ha plus, resulting in trees very close together often only 1-2 metres apart.
Strips or small patches are marked, 1/2 total tree height, to facilitate the removal of the trees. When the average age of the forest is over 100 years old and the forest has been thinned trees can be marked individually.
The timing of the harvest should coincide with a good seed year, typically 2-3 years for cedar. Establishing regeneration in cedar is not always successful so a contingency plan of planting seedlings will have to be considerrd. Cedar is a slower growing tree compared to other species.
Strips or small patches are marked, 1/2 total tree height, to facilitate the removal of the trees. When the average age of the forest is over 100 years old and the forest has been thinned trees can be marked individually.
The timing of the harvest should coincide with a good seed year, typically 2-3 years for cedar. Establishing regeneration in cedar is not always successful so a contingency plan of planting seedlings will have to be considerrd. Cedar is a slower growing tree compared to other species.
Eastern white cedar 60-80 years old
