Release Treatments

How intermediate treatments fit into a silvicultural system

Release Treatments: Weeding, Cleaning, Liberation

• Release operations are those conducted early on in the development of a stand; by definition, while the stand is in the sapling size class or earlier

• A release treatment designed to free young trees from undesirable, usually overtopping, competing vegetation.

Release Treatments: Weeding, Cleaning, Liberation

• Objectives for a release operation include:

– Reduce dense overstocking

– Protection of young trees from injury or suppression by competing vegetation

– Improving species and quality composition

– Early crop tree selection

Release Treatments: Weeding, Cleaning, Liberation

• Release is typically divided into three classes of treatment:

– Weeding

– Cleaning

– Liberation

Release Treatments: Weeding

Weeding

Conducted during the seedling stage deals primarily with herbaceous weeds and shrubs

– Done early in stand establishment to get seedlings out of herbaceous competition

• Speeds crown closure, therefore stand achieves maximum production sooner

– Objectives• In most cases, the major objective is to increase growth rates of the

seedlings.

• Secondary objective to reduce mortality that may threaten in some cases, especially when establishing trees in old fields—afforestation.

Release Treatments: Weeding

• Methods:

– Spot or broadcast herbicide

– Mechanical

• Relative growth rates:

total vegetation control > herbaceous only > woody only > no control

Release Treatments: Cleaning

Cleaning

Treatment made in a stand not past the sapling stage in order to free favored trees from less desirable individuals of the same age but different species (or inferior quality) which overtop them or are likely to do so

– Major objective is usually to control species composition by reducing mortality of favored species, but also gains many of the same benefits as thinning

– A tree needs release if an inverted cone of 90 degrees intersects branches of undesirable trees

– Should follow a survey to determine the need for release

Release Treatments: Cleaning

• Typically seek a minimum of:– 350-450 free-to-grow trees ac-1 for pulpwood, – 150-250 free-to-grow trees ac-1 for sawtimber

• Timing: the earlier, the better– Usually easier, gives more growth benefits

• Methods for cleaning:– Cutting– Herbicide: Can use a selective broadcast or an individual stem

treatment– Fire: May be too indiscriminant for most cases

Release Treatments: Liberation

Liberation

A treatment made in a stand not past the sapling stage in order to free the favored trees from competition of older, overtopping vegetation

– Primarily to reduce losses from shading (growth loss or mortality)

– Commonly removes “wolf” trees

• Large, undesirable tree, crowding out smaller, more desirable trees

Release Treatments: Liberation

• Methods for liberation– Cutting

• May treat stump with herbicide to prevent sprouting• May provide some financial return

– Girdling• Often ineffective without herbicides

– Herbicides• Usually applied by cut surface treatment

Release Treatments: Liberation

• Liberation is often used to correct past mismanagement in a stand– too many selection thinnings, commercial clearcuts, lack of

adequate site preparation etc…

• Need to manage the damage caused by removal of these culls– could be a benefit if density is too great

Other Intermediate Operations

Improvement Cutting

A cutting made in a stand past the sapling stage in order to improve composition, growth, and quality by removing less desirable trees of any species from the main canopy

– Where trees are not merchantable, this is often called TSI (timber stand improvement) and is accomplished by injecting herbicides

– Often needed in formerly mismanaged stands– Commonly applied in conjunction with thinning– May provide a commercial return, particularly where there is a good

pulpwood market

– Note: most good den trees and mast trees would be removed if improvement is applied without restriction

Other Intermediate Operations

Salvage Cutting

The removal of dead trees or trees being damaged or killed by injurious agents other than competition (e.g., insects, disease, fire, wind), in order to obtain monetary value that would otherwise be lost

– Objective is to reduce the loss of wood and money

– Often combined with other types of harvest such as thinning and sanitation

– Timing is critical—must be completed before the wood becomes unusable

Other Intermediate Operations

Sanitation Cutting

The removal of vegetation to prevent actual or anticipated spread of insects or disease; often combined with other types of harvest.

Other Intermediate Operations

Prescribed Burning as an intermediate stand treatment

– Applicable primarily in stands of thick-barked conifers

– Requires experience and expertise

– Requires investment

Other Intermediate Operations

• Objectives of prescribed fire– Reduce fuel

– Reduce competition

– Reduce insects and disease

– Improve browse and forage

– Can improve stand access for harvest or inventory

– May improve aesthetics

– For some species, improves wildlife habitat

Other Intermediate Operations

• Potential adverse effects of prescribed fire

– Can damage crop trees

– May increase erosion on erodible sites due to soil exposure

– Smoke management issues

– May adversely affect some wildlife—direct mortality or habitat degradation

Other Intermediate Operations

Forest Fertilization– An investment, so desirable only where nutrient deficiency is

limiting growth significantly

– Should apply based on diagnostic criteria

– N and P are the most commonly applied nutrients

– Timing is critical (spring or early summer)

– N application usually not a good idea at time of planting

– Fertilization can improve wildlife food availability and quantity

Other Intermediate Operations

Tree Pruning

Loss or removal of tree branches, by natural or artificial means

– Natural pruning (i.e., self-pruning) is usually initiated by shading• Shade intolerants tend to self-prune faster than shade tolerant species

– Encourage natural pruning by maintaining a high stand density

– Artificial pruning is an investment, so only use it where it pays• Intended to produce more clear (knot free) wood• Only is justifiable if the landowner is able to sell product for a premium

Pruning

Where to Prune?

Pruning

How to Prune?

What not to do!

When to Prune?

• Dead branches: can be removed any time of the year

• Conifers: may be pruned any time of year, but pruning during the dormant season may minimize sap and resin flow from cut branches

When to Prune?

• Prune hardwood trees and shrubs in the dormant season to:

– Easily visualize the structure of the tree– Maximize wound closure in the growing season after

pruning– Reduce the chance of transmitting disease– Discourage excessive sap flow from wounds

Pruning Tools

A Pruning Application: Black Walnut

A Pruning Application: Black Walnut

• Black walnut trees do not prune themselves readily– Even small branches tend to leave stubs when they die, and large

branches may hang on the tree for many years after they die

• Lateral branches can be pruned to produce high-value, knot-free wood

A Pruning Application: Black Walnut

• Pruning can begin once the trees are 10 to 12 feet tall, but should be confined to the lower half of the tree stem

• How much to prune?

– Leave at least half of the tree stem with branches

– Leaf area should be reduced by no more than 25 percent in any one year

• Prune live branches during the latter part of the dormant season, but before the trees start to grow in the spring

A Pruning Application: Black Walnut

• Prune branches when they are small, generally less than 2 inches in diameter

– Small wounds are more likely to heal over without becoming infected

– Small branches are easier to prune

– If the tree is growing well, even fairly large wounds (4 to 5 in) can heal successful

A Pruning Application: Black Walnut

• Continue to prune periodically until at least the first 9 feet of the tree is clear

– Veneer logs are normally 8 feet long

• For nut production, stop pruning at 9 feet

• For wood production, continue pruning until at least 17 feet

– Two veneer logs or one 16 ft sawlog can be produced