Shelterbelt Maintenance May 2006

André Vézina, ITA, La Pocatière Campus

Shelterbelt Maintenance

May 2006


Main activities

Weed removal Replacement of dead trees Monitoring for insects and diseases Protection against rodents and grazers Pruning


Black walnut (4 years)Chemical weed removal

Mowing

It is important to remove all weeds around the base of the trees (1 square metre), particularly around hardwoods that require a lot of water.


Glyphosate on either side of the mulch


Rototiller on either side of the mulch


Mowing on either side of the mulch


Mowing on either side of the mulch 3 times during the summer is usually sufficient to ensure proper start of growth.


Replacement of dead trees


Phytosanitary inspection


Web site of interest (in

French only)


Web site of interest


Protection against grazers

Physical barriers

Chemical repellents

Mowing on each side of the plastic mulch prevents rodents problems


Protection against deer browsing

Deer's diet and food selection slowly change over the course of the year from graze during the growing season to browse during the dormant season. There is no fixed timetable for this event, rather it's a slow transition meant to maximize the available food sources as dictated by the season. However, even when the grass is green and succulent, deer may still select the tender new growth of woody plants for food during the growing season.(source: http://www.ecostudies.org/lma_deer_resistance_strategies.html)


Protection against deer browsinghttp://www.ecostudies.org/lma_deer_resistance_strategies.html

You must plan on protecting certain plants during the warm months, typically with repellents, as physical barriers are not aesthetically appropriate for use during the growing season.

Have your physical barriers up and functioning after the first few killing frosts. If you are relying on repellents for dormant season protection, your spray program should likewise begin soon after the first killing frosts.


Use of Repellentshttp://www.ecostudies.org/lma_deer_resistance_strategies.html

Test repellents that you plan to use during the growing season. We have witnessed considerable tissue damage on new, tender growth with certain repellents, especially ones which employ "hot sauces" and blood derivatives. Soap and egg-based repellents seem to be the least damaging to plants.


Use of Repellents

Reapply repellents on a 3-week interval. Conditions must be optimum for spray applications. The temperature must be 40º F. or above for the complete drying time of the product, which can be all day in the "dead" of winter. If you apply repellents when the temperature is not optimum, or if it drops below freezing before the product dries, you will encounter winter injury on certain plants, especially broad-leaved evergreens.


Use of Repellents

Alternate repellents to enhance effectiveness. You don't want to habituate "your" deer to one repellent.

The new combinations of odor and scent-based repellents are very effective in deterring deer. Likewise, systemic repellents seem to be effective, but not for as long as the label would lead you to believe.


Food plotshttp://www.dnr.state.md.us/wildlife/ddmtdeter.asp

Under certain circumstances food plots can be effective in patterning deer away from plantings. In rural areas where large parcels are the norm, siting a food plot on the "back forty" can work. The primary factor for determining success of this technique is the amount of land involved. This method will not work in more residential areas where small lots are the norm. There is no lot size threshold to use when determining if food plots will be effective as there are so many variables which come into play; however, I would not advocate food plots unless the property involved has at least 50 or more acres. Siting food plots on smaller lots may actually attract more deer into the vicinity.


Food plots

Food plots or stations (typically employing one of the popular automatic deer feeders) must be utilized year-round to be effective.

Site the food plot as far as possible from landscape plantings. In addition, try to select a location that has cover (i.e. brush) that will further encourage the deer to frequent this site.


Scare deviceshttp://www.dnr.state.md.us/wildlife/ddmtdeter.asp

Scare devices can be effective at deterring deer damage, but, because of their adaptable nature, deer can learn to overcome their fear of some scare devices over time. Field trials of various scare devices indicated that deer can become habituated to them after a week of exposure to them. Trials of various scare devices have produced variable results.

No definitive studies have evaluated scare devices based on their effectiveness. Consumers should question manufacturers claims. Judgments should be based on testimonials and personal experiences with these products.


Dogs As A Deterrent http://www.dnr.state.md.us/wildlife/ddmtdeter.asp

Dogs can be used as a deterrent to discourage deer from feeding on some crops. A method sometimes employed is to tether a dog on a rope near the plants needing protection. The dog should scare away deer with its barking. It is important that the dog be energetic and willing to bark at the deer. Deer are adaptable and can learn to keep just out of the dog’s reach or may tolerate the dog's barking. This technique can be useful in protecting small areas


Deer fencinghttp://www.ecostudies.org/lma_deer_resistance_strategies.html

Deer fencing, typically 7.5' or more in height, can be very successful in protecting large beds or even entire properties. Woven wire and heavy duty PVC plastic fencing are very effective if properly maintained. If the integrity of your fence is compromised due to power outages (in the case of electric fences), blow-downs on fences, or poor maintenance, it will cease to function as an effective barrier. Additionally, fences must be erected quickly to be effective.


Deer fencing

Prolonged construction projects, especially with the "short" fences (typically the popular 6' high electric fences), or poor maintenance of electric fences (i.e. allowing grass or weeds to grow up through the wires, thus reducing voltage) will certainly lead to failure.

If the fence is not erected quickly, ideally in a day or two, deer will often simply jump over the short fences to enter the property. The all-important first contact with a new electric fence must be a good one (from your standpoint!). Once a deer has received a potent shock from an electric fence, it will develop a healthy respect for it and give it wide berth. The new generation of electric chargers, the "New Zealand" types, are very effective.


Credit: Stéphane Roy


Credit: Peter M. Kilburn [email protected] FREEGROW


Utilisation hints(L’écho des Forêts, june 2000 CRPF Midi-Pyénées)

The shelter-greenhouse must be removed within 3 years to avoid a too poor root development.

The conditions of growth and ventilation must stay the same during all the growing season (remove the tube for example).

The shelter-greenhouse must be used only with deciduous trees.


Inexpensive method tested in the South of Quebec

(G. Neri, Kramer nursery)


Where deer abound, it may be a good idea to plant reserve trees (height: 2 metres) to prevent grazing (credit: G. Neri)


Pruning

Information provided in this document is taken mostly from: Hubert and Courraud, 1994, Élagage et taille de formation des arbres forestiers. Institut de développement forestier de France, 304 p.


Overview

Definitions Pruning for shaping Pruning for wood quality Plant reactions


Objectives Pruning:

To produce a strong, straight tree To produce clear, knot-free timber (higher value) To ensure more even growth of diameter To promote growth in companion species To limit growth of branches over crop land

Pollarding: to remove adventitious shoots from the base of the tree


Definitions

(Hubert and Courraud, 1994)

Pruning for shaping

Fork and big branches

Pruning for wood quality

Pollarding

adventitious shoots


Pruning for shaping

Remove duplicate and multiple heads. Slow growth of branches (or remove altogether) that

may be detrimental to development of leaders.


Different stages in the life of a tree require different operations


When planting Cutting roots:

Use pruning shears to cut off damaged roots until section is ivory coloured.

Regenerate taproot very lightly. Cutting stem:

Hardwoods: remove all branches (an operation we don’t often realize).

Conifers: keep branches, except in cases where roots have been damaged.


Shearing after start of growth: If tree has started growing but does not seem

strong, do nothing except if: Multiple crowns develop or crown is

destroyed Insufficient trimming Development of suckers at the base

Different stages in the life of a tree require different operations



Development of multiple crown or destruction of crown

Cut down to a strong lateral shoot or a lateral bud, then remove all shoots in front of chosen shoot that are of same height.


Development of suckers at the base

Remove suckers, except if a given sucker seems very strong and catches up with the stem. The stem can then be replaced by the sucker. All other stalks should be removed from the base, including the main stem.


Pruning for shaping after start of growth

When plant is strong (annual growth of 30 cm or more) Correct irregular crown Slow growth or eliminate dangerous branches Remove suckers from the base Coppicing


Pinching green shoots

Pinching green shoots that are very young is efficient, not very costly and requires little time.

Should be done using the nail of the thumb: At the base of the shoot to eliminate duplicate or

multiple crowns. A few cm below the tip of strong branches that

develop too quickly.


Coppicing

Consists in cutting a plant down, close to ground level, because its structure cannot be salvaged by shearing. Should be done on vigorous plants only (annual growth of 30 cm or more).

An efficient technique on plants that demonstrate good development

André Vézina, ITA, La Pocatière Campus(Hubert and Courraud, 1994)

Coppicing

cutting the tree close to ground level choose the best stem


Pruning for shaping during growth

Pruning for shaping is done over a period of 10 to 25 years, until the factory saw log is formed (height of 4 to 8 metres).


12

3

Step #2 is not always necessary as the lateral branch may grow into the desired shape by itself.

MICHAU, E., (1985). L'élagage, la taille des arbres d'ornement. France: Institut pour le développement forestier de France. 300 p.

Leader remake

Cut of the broken leader

Attach the lateral Cut the tutor


Pruning for wood quality (reminder of objectives)

To produce clear, knot-free timber (higher value) To ensure more even growth of diameter To promote growth in companion species To limit growth of branches over crop land


Pruning for wood quality

Pruning for wood quality is a complementary operation to pruning for shaping. Both share the same main objective: producing high quality timber.

Pruning should be done early on (cheaper and more efficient) but should not hinder plant development.

Pruning should be done progressively (less traumatic for the tree).


Early pruning

Requires less time since branches are smaller. Produces more knot-free timber because the trace of

the cut is closer to the heart of the tree. Beware: if pruning is done too early, it may slow

growth, diminish trunk rigidity or cause sucker shoots to develop.


Progressive pruning

Operation is done more often, but less time is needed, overall, since branches are smaller.

Little or no trauma to trees (no sucker shoots). A single type of tool is needed. Most efficient means of improving timber quality. Highly recommended for walnut, oak and maple.


Pruning

Depends on height of tree Depends on planting density:

Trees that are spaced at 3 m or more at planting are considered to be “isolated” until their branches reach over and join. Trees located on the edge of a plantation (their outer side) are also considered to be “isolated”. Therefore, trees in shelterbelts are isolated.


Height (1st pruning)

Species Isolated In a group Walnut 3 m 4 m

Oak 3 m 5-6 m Poplar 7-9 m 12-13 m

Other broadleaved 4 m 6 m Pine 5 m 6 m

Other conifers 6 m 7-9 m


Extent of 1st pruning

Pruned off = 1/3 of total height of tree


Subsequent pruning

In the case of isolated trees: prune off 0.5 to 1 metre for every 1 to 2 metres of growth in height.

In the case of trees planted in a group: prune off 1 to 2 metres for every 2 to 4 metres of growth in height.


When to stop pruning for wood quality

Minimum height for pruning is 3 metres. Optimal height is:

7 m for poplars 6 m for conifers and hardwoods in stands 5 m for isolated hardwoods

There is no point in pruning higher than the level at which lumber will eventually be cut.

Trunk diameter at harvesting should be three times what it was at pruning.

Isolated trees: max is 1/3 of tree height. Trees in stands: max is 1/2 of tree height.


Cutting techniques

MICHAU, E., (1985). L'élagage, la taille des arbres d'ornement. France : Institut pour le développement forestier de France. 300 p.

Bark ridge

Proper cut

Branch collar

Limits between the branch and the trunk tissus

André Vézina, ITA, La Pocatière CampusMICHAU, E., (1985). L'élagage, la taille des arbres d'ornement. France : Institut pour le développement forestier de France. 300 p.

Cutting large branches

Bad

Good


The branch bark ridge will heal the wound faster and more effectively if the cut was done at the right place, if the wound is close to vertical, clean, small and smooth, and if the tree is strong (Hubert and Courraud, 1994).

Callusing of pruning wounds

Year 0 Year 1 Year 2 Year 3 Year 4



Condition of cambium and callus development

Cambium in good condition all around the wound = circular callus develops

Callus does not develop well when the cambium is in bad condition



Look for total scarring Correct cut, callus is round

Different examples of cuts


Too vertical… … callus develops on side edges only.

Improper cuts


Correlation between callus development and location of cut

B: To close to the trunk

A: Nice cut C: To close to the trunk

D: To close to the trunk E: To far from the trunk



Removal of curved branches at the base

…Avoid cuts that are either too vertical or slanted…

Removal of horizontal branches

YesNo

Yes No

Bark ridge



no

yes


Plant reactions

Taken from Shigo and Marx, 1977 as used in Hubert and Courraud, 1994

a: obstruction of vessels

b: obstruction of annual rings

c: obstruction of medullar rays

d: barrier towards the outside of the tree

Decay

Wound


MICHAU, E., (1985). L'élagage, la taille des arbres d'ornement. France: Institut pour le développement forestier de France. 300 p.

Compartmentalization is clearly visible on the cross-section of a trunk.

2: Frontal wall

3: Lateral wall

4: Wall separating old and new wood

Compartmentalization



How decay progresses after cutting

Case 1 Case 2 Case 3

Chemical barrier

Wood formed after the cut of the branch


Wood present at the cut of the branch

Good cuts Big diameter branch



How decay progresses after cutting

Case 4- Cut to close to the trunk: decay attacks the wood directly)

Case 5- Cut to far from the trunk: decay attacks all the wood present at the time of the cutting)

Wood present at the cut of the branch


Branch wood

Trunk wood

Branch left

mushroom


Depends on various factors: Visibility Callusing Sap rising Adventitious shoots Freezing

When to act


Visibility

When pruning for shaping, it is easier to see the tree structure if hardwoods are out of leaf.

When pruning for wood quality and coppicing, leaves are not so much a problem.


Callusing

The faster the callusing process, the less risk of decay (risks are minimal if branch diameter is less than 2 to 3 cm).

Cut larger branches in dormancy or close to dormancy period, just before restart of growth.


Sap rising

Discharges from cut wounds attract insects and promote decay. Also, the bark is more fragile and detaches easily from the trunk when sap rises.

For smaller branches (diameter < 3 cm): no problem. For larger branches, avoid cutting maple, birch, elm,

walnut and linden when sap rises. Active sap rising period usually runs from the end of March to the end of April.


Adventitious shoots

When shearing and pruning is too aggressive, adventitious shoots may develop. Avoid removing more than 20% of crown (source: Montreal Botanical Garden Web site)

If pruning is done at the end of July or beginning of August, risk of adventitious shoots are minimal or null.


Freezing

Avoid pruning or cutting during very cold weather. In the fall, take into account risks of frost cracks,

particularly with non-hardy species.


Branches with a diameter inferior to 3 cm: At any time, except during very cold weather. Pinching, which is done in June, is quick, effective and not very costly.

Branches with a diameter superior to 3 cm: Cut branch before sap rising or when sap flow is slowed, as close as possible to the restart of growth. To avoid adventitious shoots, prune at the end of July or beginning of August.

When to prune (overview)


How to dispose of cut branches

If branch is healthy, shred it and leave chips in the hedge.

If branch is diseased, burn it and disinfect all tools.


Only treat wounds that are larger than 5 cm in diameter Wound should be flat, clean and dry. Treatment is desirable if the part of the branch

that has been cut off contains heartwood.

Some experts question the effectiveness of this operation. Take care in selecting products to be applied.

Treating wounds


Treating wounds

Products used should: Provide effective protection from fungi and

bacteria Repel insects Be non-phytotoxic Be durable Be impervious to water but pervious to air Be non-toxic to humans and animals

André Vézina, ITA, La Pocatière Campus( Hubert and Courraud, 1994)

Summary (pruning)

a. Pinching green shots or pruning with hand pruner

b. Pruning for shaping

c. Pruning for shaping and pruning of lower branches

d. End of pruning for shaping


(Pierre Le Den / ENSP (MR & SD) + IDF)

Complete pruning for shaping by eliminating forks formed by branches that grow too vertically (A) and removing branches that compete with the main stem (B).Log of

interest

leader

Pollarding

Pruning for quality wood

Pruning for shaping or to limit the

extension of the branches into the field

BEFORE AFTER


Economical benefits

For the same species and for identically sized individuals, price increases can reach:

600% for hardwoods

85% for conifers



Pruning tools

http://www.orchardsedge.com/images/products/F2/large.jpg


Pole prunerDouble lever action

pole pruner head with rope and pull

Pneumatic pruner


Hand saws


16-foot Aluminum Extension Pole Saw

http://www.orchardsedge.com/images/products/371-42/large.jpg


Mechanical pruning: Avignon, France


Mechanical pruning: New York State


Costs

Varies with the age, composition and length of the shelterbelt

Pruning cost will also vary with the size of the branches to cut.


Estimated average cost Operation Occurrence Total

(cost/km)

1. Weed removal and monitoring for insects and diseases

2 times/year first 5 years 2 225 $

2. Replacement of dead treesonce (year 2), 10%

mortality rate 225 $

3. Protection against rodents and grazers first ten years 19 000 $

4. Shearing and pruning from year 2 to year 10 2 500 $

Total 23 950 $

Total/m/year 2,4 $

Total/m/year (without operation 3) 0,5 $

Shelterbelt Maintenance May 2006

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Transcript of Shelterbelt Maintenance May 2006