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FREE-GROWING DAMAGE CRITERIA FOR EVEN-AGED (AGE CLASS 1) CONIFEROUS TREES (Revision 5. 24 January, 2000) INTRODUCTION Before a stand can be declared free growing it must have adequate stocking of healthy, wellspaced trees of a preferred or acceptable species.. The free growing damage criteria identified in the attached guidelines are not legislated regulations. The guidelines are based on the most current knowledge of forest-damaging agents, and are provided to help users exercise their professional judgment in identifying "healthy" trees. The district manager may allow or require deviations from these guidelines, as long as the legal requirement to produce a healthy tree is met. These free-growing damage criteria are intended to help users uniformly define “healthy” as part of “healthy, wellspaced trees” used in the Forest Practices Code Act of BC and regulations. These damage criteria are designed for use at the free-growing assessment to determine the damage to, and acceptability of, individual trees (conifers only) across the province. Acceptability of a stand will depend on several factors including thresholds of damage and stocking standards agreed to in the prescription. The table lists various types of damage, causal agents and species of trees. Agents and damage are often referred to by their codes listed on the Ministry of Forests Integrated Data Dictionary Pest_Species_Code list (partly listed on the Silviculture Damage Agent and Condition Codes (FS 747) field form). Tree species abbreviations are listed in the Forest Productivity Council publication Minimum Standards for the Establishment and Remeasurement of Permanent Sample Plots in British Columbia (1999). There are two key points to keep in mind when using these criteria: 1. These criteria apply only at the time the free-growing survey is conducted and are specific to even-aged, ageclass 1 stands that are being regenerated primarily to coniferous species for the production of timber. The assumptions made on the impact of pest damage to potential crop trees are founded on these factors. 2. Broadleaf species are noted in these criteria (usually as non-susceptible host species) but there are no damage criteria listed for these species. This is because the characteristics of most broadleaf species (e.g., pests, growth habits, etc.) are sufficiently different from those of conifers that creating a single table would be difficult and confusing. It is envisioned that broadleaf species, and partial-cut stands (age class 2 and older), will be covered by separate tables in the future. These criteria are based on best available data and professional opinion, and are expected to be revised in future with newly available knowledge or information.

3 TABLE 5-1. FREE-GROWING DAMAGE CRITERIA FOR EVEN-AGED (AGE CLASS 1) CONIFEROUS TREES (REVISION 5, 24 January, 2000 ) PLEASE READ the preceding introduction before using the following table and figures. LOCATION OF DAMAGE

TYPE OF DAMAGE

STEM

• the tree has any wound which is greater than 33% of the stem circumference, or • the tree has a wound which is greater than 20% of the total length of the stem, or • the tree has a wound centred on an infection caused by a stem rust, canker or dwarf mistletoe (See Note under Stem: Infection). Insect mining under • signs of pitch tubes, boring dust, exit holes on bark bark surface, galleries under the bark • Foliage is still green Insect mining at root • the tree is currently attacked by a bark-mining collar insect such as a weevil or a beetle and exhibits symptoms such as foliage discoloration, thinning and/or reduced height growth increments Deformation • the pith is horizontally displaced more than 30 (including crook, cm from the point of defect and originates sweep, fork, browse, above 30 cm from the point of germination. and dead or broken top)

STEM

STEM

STEM

TREE BEING ASSESSED IS

UNACCEPTABLE IF:

Wound (including sunscald and girdling)

• •

•

HOST SPECIES

LIKELY DAMAGE AGENTS & DAMAGE AGENT CODES

COMMENTS

All

A wound is defined as an injury in which the cambium is dead (e.g., sunscald) or completely removed from the tree exposing the sapwood. Measure the wound across the widest point of the exposed sapwood (or dead cambium when the tree is damaged by sunscald). Healed over wounds (=scars) are acceptable. See Figure 1.

Pl, Sx, Fd

squirrel AS, beaver AZ, vole AV, porcupine AP, hare AH, Warrens root collar weevil IWW, sequoia pitch moth ISQ, fire NB, windthrow NW, sunscald NZ, logging TL, mechanical TM., cattle AC IBM, IBI, twig beetles

Pl, Sx

root collar weevil IWW

All, except Defoliators ID, white pine Cw and (spruce) weevil IWS, Hw lodgepole pine terminal weevil IWP, sequoia pitch moth ISQ, cattle AC, deer AD, elk AE, moose AM, frost NG, hail NH, snow NY, drought ND, Logging TL, mechanical TM. the tree leader has been killed 3 or more times Sx, Ss, Pl White pine (spruce) weevil IWS, lodgepole pine terminal in the last five years (weevil only). weevil IWP, All terminal weevils (IWS,IWP), the tree has two or more leaders with no frost NG, animal damage A dominance expressed after five years growth and the fork originates above 30 cm from the point of germination. the tree has a dead or broken top at a point that All is >2 cm (>3 cm for the coast) in diameter. All comandra blister rust DSC, any infection occurs on the stem. stalactiform blister rust DSS white pine blister rust DSB, western gall rust DSG, atropellis canker DSA. Pw, Pl, Py white pine blister rust DSB, an infection occurs on a live branch less than comandra blister rust DSC, 60 cm from the stem. stalactiform blister rust DSS western gall rust DSG. a gall rust infection occurs on a live branch less Pl, Py than 5 cm from the stem.

STEM

Infection • (including cankers and galls)

BRANCH

Infection (cankers)

•

BRANCH

Galls

•

BRANCH

Gouting

• any adelgid gouting occurs on a branch.

Ba, Bg, Bl balsam woolly adelgid IAB.

FOLIAGE

Defoliation

• >80% of tree foliage has been removed due to defoliating insects or foliage disease.

All

defoliators ID, foliage diseases DF

Bark beetles normally attack mature trees but are now attacking smaller stems. Only trees that are symptomatic should be checked for insect infestation or mining damage. Non-symptomatic trees are presumed to be unaffected by insect mining.

For horizontal displacement see Figure 2.

This criterion only applies for terminal weevil damage

Leader dominance occurs when the tallest leader is at least 5 cm taller than the second tallest leader. See Figure 3.

Note: Wounds caused by rodent feeding around rust cankers should have stem rust recorded as the causal agent.

See Figure 4.

See Figure 4. Gouting is defined as excessive swelling of a branch or shoot caused by balsam woolly adelgid, and is often accompanied by misshapen needles and buds. It is most common on branch tips and at nodes near the ends of branches. Consult a recent distribution map to identify the geographic extent of this pest.

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LOCATION OF DAMAGE

TYPE OF DAMAGE

TREE BEING ASSESSED IS

STEM OR BRANCH

Dwarf mistletoe infection

ROOTS

Root disease

HOST SPECIES

LIKELY DAMAGE AGENTS & DAMAGE AGENT CODES

COMMENTS

Hw, Pl, Lw, • any infection occurs on the stem or a live Fd branch, or • a susceptible tree is located within 10 m of an overtopping tree, which is infected with dwarf mistletoe.

hemlock dwarf mistletoe DMH, lodgepole pine dwarf mistletoe DMP, larch dwarf mistletoe DML, Douglas-fir dwarf mistletoe DMF.

Note: To confirm infection, the surveyor must observe mistletoe aerial shoots or basal cups on regeneration or on live or dead fallen brooms. Overtopping tree is a tree that is three or more times taller than the median height of the trees being assessed.

• sign(s) or a definitive combination of symptoms of root disease are observed.

armillaria root disease DRA, laminated root rot DRL, tomentosus root rot DRT, annosus root disease DRN, blackstain root disease DRB.

Signs are direct evidence of the pathogenic fungus including fruiting bodies, distinctive mycelium or rhizomorphs. Symptoms include foliar chlorosis or thinning, pronounced resin flow near the root collar, reduced recent leader growth, a distress cone crop, and wood decay or stain. An individual symptom is not sufficient to identify a root disease. Note: All conifer species are considered susceptible. Broadleaf species are considered not susceptible for survey purposes only. Example: How to apply net down for root disease. If root disease-infected trees are found in the plot: 1. In the first sweep, determine the total number of healthy, wellspaced trees using the prescribed minimum inter-tree distance (MITD) (e.g., 12 trees); 2. In a second independent sweep, determine the number of well-spaced infected trees (including dead infected trees and for DRT only, infected stumps) using MITD (e.g., 1 infected tree); 3. From the number of susceptible healthy well-spaced trees found in step 1, subtract the product of the number from step 2 and the multiplier for the specific root disease (e.g., for DRA: 12-1(2) = 10). The result is the adjusted number of healthy, well-spaced trees tallied for the plot. Note: Bl, Cw, Pl, Pw, Py, and broadleaf species are considered not susceptible for survey purposes only.

UNACCEPTABLE IF:

All

• infected tree found in plot. See comments for All well-spaced tree net down calculation. The multiplier for DRA is two, except in BEC zones PPdh1&2, IDFxh1, IDFdm1&2, MSdk1 and MSdm1 where the multiplier is one.

• infected conifer found in plot. See comments for well-spaced tree net down calculation. The multiplier for DRL is four. • infected conifer or stump found in plot. See comments for well-spaced tree net down calculation. The multiplier for DRT is two. • infected conifer found in plot. See comments for well-spaced tree net down calculation. The multiplier for DRN is two.

armillaria root disease DRA.

Fd, Sx, Se laminated root rot DRL. Lw, Ba, Bg Se, Sx,

tomentosus root rot DRT.

Ba, Hw, Ss annosus root rot DRN.

(Revision 5. 24 January, 2000)

Note: Ba, Bl, Cw, Fd, Pl, Pw, Py and broadleaf species are considered not susceptible for survey purposes only. Note: Bg, Bl, Cw, Cy, Fd, Hm, Pl, Pw, Py, Sx and broadleaf species are considered not susceptible for survey purposes only.

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Figure 1. Calculation of wound along stem length. (Revision 5. 24 January, 2000)

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Figure 2. Determining horizontal displacement when assessing stem deformation. This is only done when tree has five seasons’ growth after damage occurs. (Revision 5. 24 January, 2000)

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Figure 3. Acceptable and unacceptable forks

Figure 4. Distance measurement from point of infection by canker or gall to main stem. (Revision 5. 24 January, 2000)

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Definitions basal resinosis (pitching): copious exudation of pitch at the base of the stem at or below the root collar. This symptom often is associated with armillaria root disease or attack by Warren’s root collar weevil. decay: the disintegration of plant tissue. The process by which sound wood is decomposed by the action of wood-destroying fungi and other microorganisms. fork: two or more leaders have originated from the loss of a leader or apical shoot. At free-growing age, a fork is considered persistent if it has not differentiated in height between competing leaders by more than 5 cm after five years of growth since the leader damage occurred. Forks may provide entry points for decay fungi, are points of weakness during felling, and may create waste in the highest value first log. gall: nodule or lump of malformed bark or woody material caused by a variety of damaging agents, such as western gall rust and some insects. gouting: excessive swelling of a branch or shoot, often accompanied by misshapen needles and buds. Most common at nodes on branches and frequently caused by balsam woolly adelgid on true firs (Abies spp). infection: characterized by a lesion or canker on stem or branches or by swelling around the entrance point of a pathogen. injury: damage to a tree by a biological, physical or chemical agent. scar: a wound completely healed-over by callus tissue wound: an injury where cambium is dead (e.g., sunscald) or completely removed. Wounds often serve as entry points for decay fungi. B24Jan2000FGDamage.doc (based on LPCrevisedfree-grow.doc) (Revision 5. 24 January, 2000)