SREF-FH-001 February 2016

The health of your forest is import- Promoting a Healthy Forest on Your Land ant if you produce income from forestland or simply enjoy its beauty, AUTHORED BY: DAVID COYLE AND MARK MEGALOS wildlife, and other amenities. Ne- glect (even if benign), unpredictable weather events, and insects and disease can hinder a forest’s ability to provide all the benefits that accrue from healthy forests. Exotic insects, wildfire, diseases, and storms and ice have caused widespread declines in forest health. One recent example, the redbay ambrosia beetle and laurel wilt, have killed millions of redbay trees along the southeast- ern U.S. coast, and are threatening other tree species as well as avocado production. The emerald ash borer is now present in the southeastern U.S. Figure 1. This healthy longleaf pine (Pinus palustris) stand has been thinned, and understory and causes complete mortality of ash vegetation has been managed with prescribed burning. Stands such as these have abundant wildlife, diverse vegetation, and help clean our water and air. trees. Past southern pine beetle out- breaks have caused millions of dollars Healthy forests provide many public benefits like clean air and water, wildlife and millions of acres of tree damage. and plant habitat, and diverse forest products that help the economy and eco- Although forest health problems can system (Fig. 1). Healthy forests also provide individuals with a greater opportuni- discourage forest landowners, most ty to achieve their personal objectives such as the production of wood products, solutions are reasonable and can be recreational or hunting experiences, aesthetic enjoyment, or a variety of other accomplished in the course of typical goals. Healthy forests are sustainable and meet owner objectives. Additionally, maintenance actions. Practicing non-timber benefits are evident in a healthy forest; when trees are healthy, they sound forest management promotes produce nuts, cones, seeds, canopy, and leaf litter that provide food and habitat forest health! A forest management for understory plants and wildlife and enrich the soil. We define forest health as plan is the first place to start, as the ability of a forest to maintain and perpetuate a constant high quality supply knowing the steps for proper forest of environmental benefits, products, and a diverse plant and animal community. management and proper forest pro- tection are oftentimes very compat- A healthy forest means different things to different people, and can be further ible and key to attaining a healthy characterized by how it is managed (for example plantation vs. natural stand) forest. or its age (young vs. mature). Plantation forests are generally more intensively managed, productive (growing more timber per acre), and provide for higher Forest health begins with the health incomes on a more regular basis than a forest that regenerates naturally. Planted needs of a single tree. A forest forests are generally more uniform (planted in rows), have a greater chance of containing one unhealthy tree does being fertilized, and are usually harvested sooner than natural stands. Natural, not jeopardize the health of an entire or naturally-regenerated, forests may produce income less frequently and are forest. However, on occasion, an often less intensively managed. Natural forests vary in composition (different unhealthy tree can, if left alone, lead types and ages of trees), and may be primarily managed for wildlife, aesthetics, to problems throughout the forest. or non-timber benefits (for example, protecting watersheds, providing habitat or For example, lightning can damage a food for wildlife, or helping facilitate nutrient cycling). single tree by cracking the stem and

www.southernforesthealth.net 1 breaking through important pro- tection mechanisms in the bark and Factors that Jeopardize Forest Health: trunk. When a tree is wounded in this manner, it releases odors that attract Many factors can reduce or degrade ing mortality. Important exotic plants insects. These insects can attack the the health of our forests. These in the southeastern U.S. are kudzu, damaged tree, and may spread to include native and exotic pests, past cogongrass, and Chinese privet. healthy neighbor trees, contributing land uses, uncontrollable weather These plants can grow over vast areas, towards an unhealthy, insect-infested events, long term climate changes, and choke out native vegetation (Fig. forest. Similarly, a forest may have a and wildfires. 3), including trees. Exotic insects of canopy of extremely healthy trees, concern include the redbay ambrosia but have a very unhealthy ground- Native pests are those that naturally beetle and emerald ash borer, both of cover dominated by exotic plants, occur in the U.S. Major pests of pine which can kill trees very quickly. such as Chinese privet or kudzu. forests include the southern pine Exotic plants can crowd out native beetle and Ips beetles. These insects Past land management practices like vegetation, depriving it of important are attracted to the chemicals given farming/grazing and logging oper- nutrients, water and sunlight. This can off by wounded or unhealthy trees. ations where proper practices were lead to detrimental changes in plant The southern pine beetle, in particu- not used can also have a detrimental and animal communities. Removal lar, is a forest pest capable of major effect on the health of the forest. The of the exotic plants often improves forest damage and tree mortality (Fig. deforestation of our Eastern forests in forest health, but this may involve a 2). Defoliators (insects that eat leaves) the 19th and early 20th centuries for dedicated effort over several years to such as the gypsy moth and tent cater- agricultural production in the absence complete. pillars are common pests on hard- of proper conservation measures led wood trees. Most defoliators do not to excessive erosion, loss of topsoil, or There are many ways to profitably kill trees, but many years of defoliation detrimental soil structure in many parts manage and improve the vigor of can result in decreased tree health, as of the south (Fig. 4). your forests while minimizing the the loss of leaves or needles can affect risks. Some are as simple as reg- a tree’s ability to produce food. High-grading, another past land ularly monitoring your forestland, management practice is the practice while others involve planned timber Exotic pest plants and insects are of harvesting the largest, often best management. With awareness and a mostly associated with recent dis- quality trees and leaving the small little planning, most landowners can turbances, and have typically come and lower quality trees. High-grad- promote forest health while minimiz- from other parts of the world. Exotic ing is prevalent in stands with mixed ing risks along the way to achieving species can have negative impacts (multiple different) species and their objectives. As any good doctor on native trees, outcompeting native continues today as “diameter-limit knows, prevention is the cheapest plants, and changing water and cutting.” When repeated, high-grad- and most effective strategy. nutrient cycles, and ultimately caus- ing results in stands of slow-grow-

Figure 2. The southern pine beetle (Dendroctonus frontalis) is capable Figure 3. Cogongrass (Imperata cylindrica) is a non-native weed of killing thousands of trees if outbreaks occur. In this photo from the Sa- capable of outgrowing native vegetation and taking over large areas. bine National Forest in Texas, the gray loblolly pine (Pinus taeda) trees The trees in this photo will likely survive, but will have to compete in the middle are dead, the red trees closer to the outside are recently with the cogongrass for water and nutrients, and probably won’t killed, and the yellow trees are dying. In this case, the southern pine grow as quickly as they normally would. beetle outbreak appears to be expanding outwards in all directions.

www.southernforesthealth.net 2 Figure 4. Soil erosion, in this case from poor drainage that caused deep gullies and washed away much of the topsoil, can create difficult growing conditions for trees.

Figure 5. Damage from logging equipment can scrape the bark off trees, causing large Figure 6. When animals are allowed to graze so much so that the grass cannot grow fast wounds that may be infected by fungi or enough, the land can become damaged and may not grow back. This can lead to soil erosion, attacked by bark and woodboring insects. especially if it occurs on a slope, as grass or other vegetation will no longer be able to buffer flowing water after a rain. ing trees, often comprised of less site stresses trees, and stressed trees valuable timber species and reduced are much more susceptible to insects stem quality. and diseases than are unstressed trees. Growth and productivity are better Excessive logging damage occurs when trees are not stressed. when logging machinery rubs against standing trees that are not part of the Weather events include lightning, timber sale (Fig. 5). This often results high winds, snow and ice damage, in large wounds on the stems of and flooding. These can have dev- “leave” trees, which can lead to insect astating effects on trees and forests. attack and disease infection. Lightening can lead to large injuries (Fig. 7), while wind, snow, and ice Destructive grazing by livestock can (Fig. 8) can cause trees to bend and result from overgrazing, or not allow- ultimately snap. Injured trees often ing pastures the time or energy to attract bark and wood-boring insects, regrow (Fig. 6). Poor grazing practices which can potentially lead to addi- can lead to an influx of weed species, tional trees being attacked. soil erosion, soil compaction, and pasture degradation. Wildfire, if severe enough, will injure, stress or kill trees (Fig. 9). These trees, if “Off-site” tree species not well-suited they survive, will be left susceptible to to a site can become very stressed and various types of insects and diseases. unhealthy. For example, some trees do Insect damage after a fire may result in Figure 7. Trees struck by lightning don’t al- not grow well on very wet sites, while tree death. Also, very hot fires can kill ways die, but the wounds created can attract bark and woodboring insects. These insects others do not grow well on very dry tree roots, damage the soil, and hinder may colonize the tree, and are capable of sites. Selecting species for the wrong its ability to support new growth. infecting the tree with fungi.

www.southernforesthealth.net 3 Figure 8. During storms, snow and ice can accumulate in tree tops Figure 9. Uncontrolled wildfire can destroy everything in its path. and cause stems to break. In this stand in South Carolina, several Wildfires in Georgia in 2007 burned over 500,000 acres and trees have snapped because the tops became too heavy from ice destroyed nine homes. accumulation during a storm in 2014.

What Can Be Done to Achieve a Healthy Forest?

Since it is very difficult and expen- your forest for evidence of insect or disease infestations or other • Monitor sive to treat forest health issues in a forest health issues often. When potential problems are observed, use forest – especially insect and disease control techniques to minimize the spread of many insects and diseases infestations – prevention strategies and/or salvage affected stems. Monitoring will also help you know when are best. Prevention should be certain silvicultural treatments are needed, like fertilization, prescribed practical and cost-effective. Often, burning, or thinning. professional foresters are well-quali- fied to assist you in making decisions your decisions about reforestation (including species selection), site • Modify to promote your forest’s health. preparation techniques, seedling grading and handling and proper planting Foresters who work with public and technique to be specific to the soils, history and location of the forest in private agencies such as consulting order to ward off potential insect and disease outbreaks. firms are often well versed in forest health prevention strategies. Follow your trees to sustain a healthy, vigorous forest. Thin trees to • Manage the three M’s: Monitor, Modify, and prevent over-stocked and over-mature conditions that can stress forests. Manage. Prevention steps include: Address any health issues quickly to prevent spread to other trees.

UNDERSTAND YOUR FOREST & ITS growth? Certain soils have better have the ability to obtain oxygen. All POTENTIAL HEALTH PROBLEMS: drainage than others, so tree roots of these conditions can make trees won’t be submerged after hard rain more susceptible to pests and diseases. Understanding forest health requires events. Some soils have a hard clay that you know what natural resources layer just below the surface, and this - Are my timber species well-suited are present and their condition. may impact seedling’s ability to grow for my soils? Remember to consider These resources include trees, soils, roots. Sometimes, soils need to be soil limitations and tree condition. vegetation, water resources, and “ripped” prior to planting to break Certain types of trees will grow better wildlife. Understanding site limitations the clay layer so tree roots can grow on certain types of soils. For instance, begins with a thorough knowledge to deeper depths. longleaf pine tends to grow better on deep, sandy soils than loblolly pine. of soils, as it is the best way to - What are the conditions of my soils? determine a forest’s potential growth, Are they eroded or compacted? - What is the growth potential of productivity and its susceptibility to Growing on these types of soils can trees on my soils? This is referred to pests and disease. Some important stress and weaken trees. Are there as “site index” (SI) and it is the pre- questions to ask regarding soils are: deep washed-out-gullies? Roots of dicted height of a tree species at a nearby trees may be exposed by given age, usually 25 or 50 years. - What are the major soil types of my running water and erosion. Are they The higher the SI for a species, the forests? What does that mean for tree wetlands? Submerged roots don’t taller the trees will grow and the

www.southernforesthealth.net 4 greater the production. Site Index plan for your forests in order to - Promote regeneration of desirable varies among soil types and locations, develop active management steps species suited to soil type while and it is important to be aware of the that will likely be required to return avoiding overstocking (too many trees capabilities of a site and plant with your forest to desirable conditions. per acre). tree species that have the best chance A written management plan includes to grow and perform well. - Thinning to maintain adequate an assessment of the condition growing space for trees. of the forest and outlines how to Soil information - Employ practices that protect water Help is Available! accomplish your management goals is readily available through your quality and soil productivity, including for your land. State forestry agency harvesting practices. county (or “District”) Natural personnel, and consulting and/or Resources Conservation Service registered foresters can develop - Use prescribed fire where feasible to (NRCS) office. They can help you management plans. reduce fuel loading and reduce risk identify and interpret your soil from catastrophic wildfire, remove information. A service forester with A good management plan contains: understory competition, and improve your state forestry agency or a private habitat for wildlife. consulting forester can assist you in - A statement of your goals and understanding the species suitability objectives for your forestland. - Remove or cull diseased trees. and growth potential of your soils (contact information is listed in - A map or aerial photograph showing - Control exotic plants that hinder desirable plant and wildlife species. the back page of this publication). property and stand boundaries, access Additionally, most soil surveys are points, and important features such as available on the NRCS website: roads, water bodies, and structures. MONITOR FREQUENTLY! http://www.nrcs.usda.gov/wps/ - A forest description, including soil Forests should be inspected annually portal/nrcs/soilsurvey/soils/survey/ types, site index, number of acres, (or better yet, quarterly) in times state/. Once there, select your state, tree species, stand age, stocking, of stress to identify forest health then select your county. average height, tree condition, and problems. An insect pest such as the health and topographic information. southern pine beetle can take over Additional forest resource information A management plan may also include quickly. Monitoring during different can be obtained by having a consult- more specific inventory data such as seasons is more informative than at ing forester visit your forest. Pertinent timber volumes and values. one time during the year, as it gives forest resource questions include: you the opportunity to see things - A timetable of prescribed forest that may not be evident year-round. - What are the dominant tree species management activities, including Inspection for specific pests should be for each forest stand? thinning, final harvesting, regeneration plans, wildlife practices, and treatment done on a schedule that’s appropriate - How old are the dominant trees in plan for problems such as insects, to the problem. When scouting for the forest canopy? disease, or exotic plants. pests, one dead tree may not be cause for concern, but several dead or - What is the present stand condition? An excellent source of information dying trees may warrant a closer look. For example, are there slow growing regarding forest management is Thinning crowns on individual trees species, or crowded trees that will the Forest*A*Syst website: throughout the stand may reflect poor increase the risk of insects or disease? www.forestasyst.org. This site allows site conditions or drought, but a patch you to specify your management of trees with thinning crowns may - Are there any current disease or objectives, and combine this informa- indicate a pest problem. Inspection for insect problems? tion with site-specific environmental storm damage should be done soon data to assemble a written forest Are exotic plants a potential threat? after a storm event. Salvage value - management plan. If so, what are the recommended diminishes with time and damaged or control measures? downed trees can serve as hosts for MANAGE FOR GOOD FOREST insect pests. HEALTH AS A PART OF YOUR PLAN DEVELOP A FOREST MANAGE- Landowners can access resources from MENT PLAN: A proper management plan should address specific practices that the Internet to become familiar with Proactive forest management promote forest health and reduce insect and disease symptoms. Sever- promotes forest health and reduces risks. One or more of the following al such sources are listed on the last risks. You will need a management practices may be recommended: page of this publication. For a list of

www.southernforesthealth.net 5 Table 1. Online resources for forest health potential threats, monitoring schedules, and symptoms.

http://southernforesthealth.net/insects/southern-pine-beetle

http://entnemdept.ufl.edu/creatures/trees/southern_pine_beetle.htm Southern pine beetle http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsbdev2_042840.pdf

http://www2.ca.uky.edu/entomology/entfacts/ef443.asp

http://www.emeraldashborer.info Emerald ash borer http://southernforesthealth.net/insects/emerald-ash-borer http://na.fs.fed.us/fhp/eab/

http://www.freshfromflorida.com/Divisions-Offices/Plant-Industry/Agriculture-Industry/Pests-Dis eases/Laurel-Wilt-Disease

Redbay ambrosia beetle http://southernforesthealth.net/fungi/laurel-wilt

and laurel wilt http://www.ncforestservice.gov/forest_health/forest_health_laurelwiltfaq.htm

http://www.forestry.alabama.gov/LaurelWilt.aspx?bv=3

http://southernforesthealth.net/insects/gypsy-moth

http://www.fs.fed.us/ne/morgantown/4557/gmoth/ Gypsy moth http://www.na.fs.fed.us/SPFO/pubs/fidls/gypsymoth/gypsy.htm

http://www.vdacs.virginia.gov/plant&pest/moth.shtml

http://southernforesthealth.net/weeds/cogongrass

http://www.cogongrass.org/ Cogongrass http://www.invasivespeciesinfo.gov/plants/cogongrass.shtml http://www.freshfromflorida.com/Divisions-Offices/Florida-Forest-Service/Our-Forests/For est-Health/Invasive-Non-Native-Plants/Cogon-Grass

http://www.nps.gov/plants/alien/fact/imcy1.htm

http://plants.usda.gov/plantguide/pdf/pg_lisi.pdf

http://southernforesthealth.net/weeds/chinese-privet

Chinese privet http://ipm.ifas.ufl.edu/environmental/Chinese_privet.shtml

http://www.invasiveplantatlas.org/subject.html?sub=3035 some major potential threats to forest reduce the condition and potential of potential of future forests due to health, suggested monitoring sched- forests. Trees damaged by machinery soil compaction and “rutting.” Hire ules, and the symptoms, see Table 1. can attract insects and disease, and a consulting forester to act as your logging debris can increase wildfire agent and include provisions in the risks. Since the majority of the forest’s contract to monitoring logging jobs TIMBER HARVESTING CAN IMPACT root system is in the top 12” of soil, at least daily during logging activity. FOREST HEALTH improper use of equipment on fragile For more information on selling your Poor logging practices can undo soils or logging during wet weather timber, please see the resources page years of good management and can drastically reduce the growth of this publication.

www.southernforesthealth.net 6 many other factors have shaped your will help you sustain or restore your Summary: forest. If your forest is healthy and forest resources for the future. vigorous, then it will be able to meet Forest health begins with the health your wildlife, recreation, and timber A healthy forest is an achievable of a single tree, and the goal should production needs. Many insects and goal. Obtain professional assistance be to strive to maintain or improve diseases can be prevented or con- and manage to prevent and minimize forest conditions through respon- trolled by minimizing damage to tree loss. Despite numerous factors that sible management and planning. stems, thinning stands to maintain can’t be controlled (such as drought, Forest health is partly dependent vigor, and selecting the right species wildfires, and storm damage), a forest on the landowner’s management for your soils. In addition, proper tim- landowner can manage their land to objectives, land history, and current ing of your forest management steps reduce their risks from disturbances environmental conditions. Past land also helps prevent and minimize and maximize their forest health. Our use, past forest management and risks. When you are ready to harvest, collective efforts can make our forests harvesting decisions, presence or carefully planned timber harvesting, healthier, more productive and keep absence of natural disturbances, and reforestation and stand management them sustainable.

AUTHORS:

David Coyle, Extension Associate, Southern Regional Extension Forestry and UGA – D. B. Warnell School of Forestry and Natural Resources

Mark Megalos, Extension Associate Professor, North Carolina State University

SREF-FH-001 | www.sref.info A Regional Peer Reviewed Technology Bulletin published by Southern Regional Extension Forestry

Southern Regional Extension Forestry (SREF) is a diverse team of trained natural resource educators, IT specialists, graphic designers, communi- cations and marketing experts, and media and content producers. SREF works closely with the Southern Land Grant University System, US Forest Service, and state forestry agencies to develop content, tools and support for the forestry and natural resource community. To find out more about SREF programs please visit www.sref.info.

Photo Credits:

Figure 1: Chuck Bargeron, University of Georgia, Bugwood.org

Figure 2: Ronald F. Billings, Texas A&M Forest Service, Bugwood.org

Figure 3: Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org

Figure 4: USDA Forest Service Southern Research Station, Bugwood.org

Figure 5: Robert L. Anderson, USDA Forest Service, Bugwood.org

Figure 6: R.L. Hamblen, Bugwood.org

Figure 7: Stephen F. Austin State University, Bugwood.org

Figure 8: David Coyle, University of Georgia, Bugwood.org

Figure 9: Georgia Forestry Commission, Bugwood.org

www.southernforesthealth.net 7 Resource Information: FOR MORE INFORMATION ON HOW TO SELECT A CONSULTING FORESTER, GO TO:

FOR THE LOCATION AND PHONE NUMBERS OF STATE http://msucares.com/pubs/publications/p2718.pdf AGENCIES IN THE SOUTHEASTERN U.S. PROVIDING http://texashelp.tamu.edu/011-disaster-by-stage/pdfs/ FORESTRY ASSISTANCE AND INFORMATION, SEE THE recovery/ER-038-Selecting-a-Consulting-Forester.pdf FOLLOWING WEBSITES: http://www.uaex.edu/environment-nature/forestry/FSA- Alabama Forestry Commission: http://www.forestry.alabama.gov/ 5019.pdf

Arkansas Forestry Commission: FOR MORE INFORMATION ON SELLING YOUR http://forestry.arkansas.gov/Pages/default.aspx TIMBER, GO TO:

Florida Forest Service: http://www.ncsu.edu/woodlands/woodswise/timber.pdf http://www.floridaforestservice.com/ http://www.gfc.state.ga.us/resources/publications/ Georgia Forestry Commission: SellingYourTimber.pdf http://www.gatrees.org/ http://www.mfc.ms.gov/selling-your-timber.php Kentucky Division of Forestry: http://forestry.ky.gov/Pages/default.aspx https://vtechworks.lib.vt.edu/bitstream/ handle/10919/24648/VCE420_160_2004. Louisiana Department of Agriculture and Forestry: pdf?sequence=1&isAllowed=y http://www.ldaf.state.la.us/ http://extension.missouri.edu/p/G5051 Mississippi Forestry Commission: http://www.mfc.ms.gov/ FOR INFORMATION ON RECOGNITION AND CONTROL OF EXOTIC PLANTS, GO TO: North Carolina Forest Service: http://www.ncforestservice.gov/ http://southernforesthealth.net/weeds

Oklahoma Forestry Services: http://nps.gov/plants/alien/ http://www.forestry.ok.gov/ http://se-eppc.org/

South Carolina Forestry Commission: http://www.bugwood.org/weeds/forestexotics.html http://www.state.sc.us/forest/ http://www.invasivespeciesinfo.gov/plants/main.shtml Tennessee Division of Forestry: https://www.tn.gov/agriculture/section/forests FOR SPECIFIC INFORMATION REGARDING FOREST Texas A&M Forest Service: HEALTH ISSUES, INCLUDING STORM DAMAGE, PESTS, http://texasforestservice.tamu.edu/ AND DISEASE, GO TO: http://southernforesthealth.net/ Virginia Department of Forestry: http://www.dof.virginia.gov/ http://www.nps.gov/yose/learn/nature/forest-pests.htm

http://www.forestpests.org/ TO LOCATE A CONSULTING FORESTER: http://ncforestservice.gov/forest_health/forest_insects.htm Association of Consulting Foresters: http://www.acf-foresters.org/acfweb. https://www.arborday.org/trees/health/issues.cfm Click on “Find a Forester”, then select your state in the “People Search – Public” search page. https://www.tn.gov/agriculture/article/ag-forests-storm- damage

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