Assessing Ice and Snow Storm Damaged Forest Stands

Transcription

1 Assessing Ice and Snow Storm Damaged Forest Stands March 2014 E. David Dickens, David J. Moorhead UGA WSFNR, Brent Allen, Mark Crosby, Peyton Sapp, Pamela Sapp, Bill Tyson UGA CAES, Chip Bates and James Johnson - GFC Moderate to severe ice and snow storms impact portions of Georgia almost every year and these weather events often impact both urban and rural forests. Land managers are often faced with evaluating these areas to determine if salvage or partial removal is needed, or if the stand will recover without intervention. Damage within a given area can vary greatly so careful evaluation of the damaged area should always be the first step. Decisions are often made on the worst areas within the damaged stand, and damage can vary to the point where areas within the same stand must be treated differently. This information is not meant to be a complete guide, but rather highlight points that should be considered, when evaluating and managing storm damaged areas. Severe events such as ice and snow storms tend to cause tree breakage, and immediate losses, while less severe storms may leave trees damaged and standing or partially uprooted where the stems may live for a period after the event. Prompt assessment of the severity of stand damage, and determining management options is critical to recover value of damaged stands. Tract and/or stand size, local mill product specifications, availability of harvest crews, and severity of localized damage on the ability of mills to utilize salvaged wood will impact a landowner s options and ability to conduct salvage operations in a timely manner. In general, following storms that cause immediate breakage of stems, the damaged trees must be salvaged within a short period of time, typically within one to two months of the storm event (a longer time-frame for winter storms). When trees have stems intact but have limb, crown breakage or have been uprooted, either partially (leaning trees) or completely (stem is close to ground with some roots intact), allow for much longer salvage windows. Trees with severe root damage rarely survive the growing season but can last much longer if the weather event occurs during the cooler seasons of the year, as is the case for ice and snow storms. Opportunistic insects and tree diseases will often find these weakened and stressed trees and hasten mortality so they should be considered when evaluating storm damaged stands. Generally loblolly pine stands are least susceptible to ice and snow damage (Photos 9 and 12) while slash (Photos 10 and 11) and longleaf stands (Photos 13-15) are more susceptible to ice and snow damage. Recently thinned (within the last two years) pine stands (Photo 11) are more susceptible to ice and snow damage than unthinned stands or stands that have been thinned for a number of years (Photo 12). Pine stands less than 3 to 5 years old are generally less susceptible to ice and snow damage than stands that are 5-20 years old. Older stands with diameters greater than inches tend to have less ice and snow damage than merchantable stands with smaller diameter stands. Pine trees leaning less than 45 degrees and shorter than 30 feet tall tend to straighten during the first growing season after the storm. Trees leaning more than 45 degrees and over 30 feet tall generally will not straighten to an upright position. Trees with broken tops will typically fork if relatively young (less than years old; Photo 17) or look like a squirrel nest area (Photo 18). Trees with 3 or 4 more large living branches will usually live through the storm (Photo 19) but may not grow as fast due to lower amount of crown. Each forest landowner has a set of objectives for his or her forestlands. For pine stands that are merchantable (of size to be sellable to a logger, commonly at least 15 years old), the key in each case is to determine a minimum number of trees per acre (TPA) or basal area per acre (BA/ac; Table 3 and photo 20) that are in good condition and well-spaced to grow out to rotation (or for natural regeneration). (1) If timber production is a top priority and full site resources utilization is of high importance then some minimum number of TPA or BA/ac (trees per acre and their diameters). This minimum TPA may be 150 or a BA/ac of at least 60 square feet. (2) If wildlife is the highest priority, a lower TPA or BA/ac may be attractive to the landowner; typically around 100 to 150 TPA or 40 to 60 BA/ac. (3) If natural regeneration (using the remaining pines in good condition as the seed source for the next rotation) is the objective after an ice or snow storm; then 10 to 30 TPA or 10 to 30 BA/ac in many cases will

2 provide enough seed in a bumper crop year to start a future pine stand. The minimum TPA and BA/ac recommendations in the following section on Assessing stand damage and categorize are based on full site utilization and timber production as the top priority. If a lower TPA and BA/ac is acceptable to a landowner, then use those lower numbers. Refer to Table 3 for TPA and BA/ac estimations based on an average merchantable diameter. Keep in mind that there is a minimum stand size for loggers to move to a tract and log. Generally minimum stand size for a logger is 30 to 40 acres (at least one week of work). In cases where a larger (greater than acres) pine stand has severe damage and the best option is a clearcut but 5 to 25 acres parts of the stand may not need clearcutting these smaller parts of the stand may be best included in the clearcut rather than leaving these areas. These smaller 5 to 25 acres stands are harder to sell unless loggers are in an adjacent tract in the future. Assess stand damage and categorize (1) Severe: greater than 50% of the stems with significant damage where best option is a salvage operation,) (2) Moderate: 20-50% of the stems with significant damage, but there are enough crop trees per acre in good condition to provide a stand to manage with some silvicultural work. (3) Low: less than 20% of stems with significant damage, stands that need little immediate care. Merchantable pine stands (age 15+ years)-- Levels of damage: SEVERE: (greater than 50% of the stems with significant damage) with at less than 150 trees per acre or less than 60 sq feet BA/ac standing and in good condition (little to no visible lean, small to no visible wounds). Photos 1& 2 are examples of severe damage. Options. Perform a salvage operation (clear-cut) as soon as possible to include removal of standing trees along with storm damaged wood. Post salvage options for reforestation include: (1) Pile debris, limbs, and tops away from standing trees and burn piles with burn permit under appropriate weather conditions. (2) Prescribe burn site with debris not moved to reduce debris level (fire breaks in place) then wait 2 to 3 months after burn and apply pre-plant site preparation herbicide treatment in late summer or fall. In all burning case get a burn permit before burning. (3) Chemically treat or mechanically prepare the site for planting without burning (or burn 2-3 months after the chemical or mechanical treatment). Plant quality seedlings in December - February. If salvage operations are conducted after June, site preparation will likely have to be held over until the following growing season to allow sufficient resprouting of vegetation to insure herbicide uptake and translocation to roots for most effective competition control. Regeneration weevils could be a problem following planting after mid- to late-season harvests (harvests after 30 June). MODERATE: (20-50% of the stems with significant damage) with at least 150 trees per acre or at least 60 sq feet BA/ac standing and in good condition (little to no visible lean, small to no visible wounds). Photos 3 & 4 are examples of moderate damage. Option 1. A salvage thinning operation, when feasible, leaving standing trees to be the final crop for a harvest in the future. Post salvage thinning options: (1) Pile debris, limbs, and tops away for standing trees, burn piles under appropriate weather conditions taking care not to scorch crowns of standing trees. (2) Prescribe burn the site with debris in place (not moved) in the first winter after the storm event under proper weather conditions with firebreaks in place. (3) Do not burn but keep an eye on the stand every 2 to 3 weeks for beetle activity or other problems. Option 2. Salvage when Option 1 is not feasible to include removal of standing trees. If harvest is completed in late spring, site prepare in mid- to late-summer and plant in December-January as in Severe damage post-harvest options listed above. If harvest is delayed until summer, consider delaying site preparation and planting until the following growing season to allow resprouting of vegetation before herbicide treatment. There are options for late summer early fall site preparation treatments depending on pine species to be planted. LOW: (less than 20% of stems with significant damage) more than 200 trees per acre or at least 80 sq feet BA/ac standing and in good condition (little to no visible lean, small to no visible wounds). Photos 5 & 6 are examples of light or low damage.

3 Option 1. No salvage thinning or clearcut may be required due to low level of damage. Keeping an eye on the stand for possible beetle outbreaks every two to three weeks is recommended the first growing season after the storm event. Option 2 Salvage operation removing broken stems and lean trees (trees with a visible lean). In many cases there may not be enough trees per acre to make the logging operation attractive to the logger. Prescribe burn stand where feasible the first winter after the weather event with adequate firebreaks and good weather conditions. Grow stand out to desired rotation. If a landowner has multiple stands with moderate to severe damage; prioritize the stands with the highest valued wood (sawtimber and poles) and get to these stands first, move to lesser valued stands next (chip-n-saw) and least valued stands last (pulpwood). Pines are sold by weight and broken top trees with no live crown are losing weight (1/2 of a pine tree weight is water) so time is money. Get professional help from a reputable registered forester that works the area, the State Forestry Commission, and County Agents. Attend educational workshops for help with decision-making and use good forestry web sites for more information like: gatrees.org, bugwood.org, forestproductivity.net, and Table 1 lists a timeline for salvaging timber. In all damaged stand cases, monitor the site every 2-3 weeks for beetle outbreaks or disease (root rot, pitch canker, etc.). Table 2 lists timeline for insect and disease infestations. Pre-merchantable pine stands (from age 1 to 20 years) -- Levels of damage: Generally stands with tree heights less than 30 feet and stem (main trunk) lean less than 45% will recover and straighten back in 6 to 12 months. Assess the stand for lean and stem breakage to determine action. If there are 300 to 350 stems that are in good condition (lean less than45% and no stem breakage or stem breakage above 16 feet) the stand can be carried out to thinning age. Top breakage estimates (trees per acre with broken stems and heights at the break) should be made to determine if some of these trees will have a clean log of at least 16 feet. If the top break is less than 16 feet high, these trees will be sold as pulpwood once they are merchantable under current wood utilization conditions. Where pine straw is raked and sold, these stands that have reasonable stocking (greater than 300 to 350 trees per acre with a decent crown) can be rehabilitated with some work (cutting, piling, and mowing). Note photos 9, 10, and 13 through 16 for levels of damage in young, pre-merchantable loblolly, slash, and longleaf stands. Hardwood and mixed pine-hardwood stands Hardwood and mixed pine hardwood stands suffer ice and storm damage ranging from uprooting and top and branch breakage. Assess these stands in a similar manner as pine stands from severe, moderate to low and prioritize action in stands that need salvage, Table 1. Timeline for timber to be salvaged to prevent degradation (tree species, storm event time of year, weather and market conditions can vary the harvest window guidelines)* Product Harvest window Comments Pine and hardwood veneers 4 6 weeks Blue stain could prohibit use Pine dimension lumber 3 4 months Should be kiln dried to prevent emergence of secondary pests Pine posts 4 6 weeks Blue stain will affect toughness and preservative treatment Pine and hardwood pulp, fiberboard, particleboard and OSB 8 12 months (can be as little as 2-3 months for pine pulpwood if bark starts to slough off trees when harvested) As wood begins to decay, pulping process will be affected.

4 Table 2. Timeline for invasion of damaging insects and diseases Species Year one Year two Pine Bark beetles, ambrosia beetles, Decay fungi sawyers, blue stain fungi, soft rot fungi Oak and Hickory Wood borers, ambrosia beetles, Sapwood decay fungi sawyers, soft rot fungi Other hardwoods Wood borers, ambrosia beetles, sawyers, soft rot fungi Sapwood and heartwood decay fungi *adapted from North Carolina Forest Service Division of Forest Resources Does the stand qualify as a casualty loss for tax purposes? Ice and snow storm damaged stands qualify as casualty losses as they are classified a sudden loss. Casualty losses are deductible in the year of the casualty on IRS Form 4684, Casualty and Thefts (Gaddis and Dicke 2006). The storm damaged stand qualifies as a casualty loss as the lesser of the fair market value (FMV) loss in timber and the timber basis. Timberland owned for more than one rotation will often have a zero basis whereas timberland recently purchased (i.e., $1800 per acre for 100 acres of loblolly purchased in 2010 having $750 in a land basis and $1050 in the timber basis) may have some timber basis. If the landowner has a timber basis, then a registered forester will need to estimate (1) the FMV of the timber pre-casualty (if not known), (2) the FMV following the casualty (# 1 and #2 by timber cruise) with the FMV loss = FMV before FMV after (often the salvage value), The FMV loss is deductible up to the timber basis, and (3) the basis in timber (Wang and Greene 2013). Literature Cited Gaddis, D. A. and S. G. Dicke Frequently asked questions about timber casualty losses. Publication Mississippi State University, Extension Service. North Carolina Forest Service Division of Forest Resources Timber salvage guidelines. Raleigh, NC. 2 p. Wang, L., and J. Greene Tax Tips for Forest Landowners for the 2013 Tax Year. U.S. Department of Agriculture Forest Service Southern Region Cooperative Forestry Technology Update. Southern Research Station Management Bulletin R8-MB Photo 1 & 2. Examples of a severely damaged pine stand with less than 100 good crop trees per acre.

5 Photo 3 & 4. Moderate ice damaged stands with 100 to 150 trees per acre in good condition to thin back to and grow out to rotation. Photos 5 & 6. Examples of light pine stand damage with a low priority for a salvage cut. Photos 7 & 8. Clearcutting in the foreground of left photo and right photo in pine stands with moderate to heavy damage.

6 Photos 9 & 10. A 14 year old loblolly stand (left photo) with minimal damage and minimal broken tops and an adjacent 14 year old slash stand (right photo) with numerous tops broken. Photos 11 & 12. A recently thinned slash stand (left photo) with moderate to heavy damage and an adjacent loblolly stand (right photo) with light damage thinned 4-5 years ago. Photos 13 & 14. Examples of young longleaf ice damage, various levels of lean, broken branches and broken tops. Generally trees leaning more than 45 degrees and over 30 feet will not straighten back up (younger, shorter trees have a better chance of straightening up).

7 Photos 15 & 16. Young old-field planted longleaf (left photo) with moderate to heavy top breakage and an adjacent young slash stand (right photo) with negligible ice damage or top breakage. Photo 17 & 18. Photo 17 (left photo) with a fork where storm damage broke the terminal growth and photo 18 (right photo) with a broken top from the same storm. If the fork or broken top is at least 17 feet above the ground, then the tree may have chip-n-saw or sawtimber value to that height.

8 Photo 19 and 20. Left photo - a broken top living loblolly pine with 4 live limbs, 6 years after a storm event. Right photo a 32-year-old loblolly pine wood disk dbh; 4.5 feet above groundline) showing examples of a 6, 9, and 12 dbh tree and basal area per tree (Table 3) and dbh for pulpwood, chip-n-saw, and sawtimber categories. Table 3. Southern pine basal area per tree, target minimum per acre (BA/ac) based on average dbh (diameter at 4.5 feet above groundline), and target minimum trees per acre (TPA) in good condition and well-spaced. Average dbh Basal area/tree TPA for 60 sq ft TPA for 30 sq ft TPA for longleaf TPA for (inches) (square feet) BA/ac (for BA/ac (for natural regen loblolly/slash timber prodn) wildlife) natural regen