Fire-damaged Trees Research Articles

Forest Fire Influence on Tomicus piniperda-Associated Fungal Communities and Phloem Nutrient Availability of Colonized Pinus sylvestris

Forest fire is known to positively affect bark beetle populations by providing fire-damaged trees with impaired defenses for infestation. Tomicus piniperda, the common pine shoot beetle, breeds and lays eggs under the bark of stressed pine trees and is considered a serious forest pest within its native range. Wood-colonizing fungi have been hypothesized to improve substrate quality and detoxify tree defensive chemistry to indirectly facilitate tree colonization by beetles. While some bark beetle species form symbiotic associations with fungi and actively vector their partners when colonizing new trees, T. piniperda does not have mycangia or body hairs for specific vectoring of fungi. To explore the T. piniperda-associated fungal community for signs of specific association, we used ITS metabarcoding to separately characterize fungal communities associated with surface and gut of male and female beetles. We also characterized the temporal changes in fungal community and nutrient status of pine phloem with and without beetle galleries. Sampling was performed 2 years after a natural forest fire and included both burnt and unburnt sites. In our study system, we find that forest fire significantly impacts the fungal community composition associated with T. piniperda and that fire may also indirectly change nutrient availability in phloem to beetle galleries. We conclude that T. piniperda can vector fungi to newly colonized trees but the absence of positive effects on substrate quality and minimal effects of sex indicate that vectoring of associated fungal communities is not a strategy associated with the T. piniperda life cycle.

Post-fire effects on development of leaves and secondary vascular tissues in Quercus pubescens.

An increased frequency of fire events on the Slovenian Karst is in line with future climate change scenarios for drought-prone environments worldwide. It is therefore of the utmost importance to better understand tree-fire-climate interactions for predicting the impact of changing environment on tree functioning. To this purpose, we studied the post-fire effects on leaf development, leaf carbon isotope composition (δ13C), radial growth patterns and the xylem and phloem anatomy in undamaged (H-trees) and fire-damaged trees (F-trees) of Quercus pubescens Willd. with good resprouting ability in spring 2017, the growing season after a rangeland fire in August 2016. We found that the fully developed canopy of F-trees reached only half of the leaf area index values measured in H-trees. Throughout the season, F-trees were characterized by higher water potential and stomatal conductivity and achieved higher photosynthetic rates compared to unburnt H-trees. The foliage of F-trees had more negative δ13C values than those of H-trees. This reflects that F-trees less frequently meet stomatal limitations due to reduced transpirational area and more favourable leaf-to-root ratio. In addition, the growth of leaves in F-trees relied more on the recent photosynthates than on reserves due to the fire disturbed starch accumulation in the previous season. Cambial production stopped 3weeks later in F-trees, resulting in 60 and 22% wider xylem and phloem increments, respectively. A novel approach by including phloem anatomy in the analyses revealed that fire caused changes in conduit dimensions in the early phloem but not in the earlywood. However, premature formation of the tyloses in the earlywood vessels of the youngest two xylem increments in F-trees implies that xylem hydraulic integrity was also affected by heat. Analyses of secondary tissues showed that although xylem and phloem tissues are interlinked changes in their transport systems due to heat damage are not necessarily coordinated.

Dynamic of Radially Growth Trees Damaged by Fire in Pine Stands Steppe Zone of Kharkiv Region

Purpose. The study of pre- and after the fire of pine forest stands forest steppe Harkivschyny. Methods. Dendrochronological. Results. Dynamics of results of dendroclimatic and dendroindication researches of pine stands on three permanent research plots damaged by fires in 2011. Trees that have good sanitary state and dominant trees restore the tree radial growth in 2 -3 years, at the same time trees in most damaged stand where height of deposit on tree stems are 3.87, didn’t revive the radial growth still. Significant relationships between defoliation and the radial growth for 2013 for second research plot (height of deposit on tree stem is 1,87 м) When the radial growth start to revive. This regression model was described by curves of third degree. Conclusions. It was found that less fire damaged trees that have the best sanitary conditions and are predominant, restored radial growth for 2 - 3 years.

Erratum to: Effects of forest fires on forest ecosystems in eastern coastal areas of Korea and an overview of restoration projects

Recent large fires have highlighted the importance of understanding post-fire processes in forest ecosystems, in order to implement ecologically sound post-fire forest restoration practices. Restoration principles should be based on a thorough understanding and appropriate integration of the ecological, social, and economic factors associated with forest ecosystems. In Korea, forest fires mainly affect pine forests, which provide habitats for pine mushrooms, a major source of income for local residents. Curculionid beetles can easily attack fire-damaged trees because of the trees’ weakened defense mechanisms. On the other hand, fire accelerates the decomposition of organic matter and nutrient release, thereby improving forest productivity. Natural restoration after large fires depends on regeneration (e.g., from seeds and sprouts) of the remaining trees that have sustained less damage, until secondary forests are established. However, severely burned areas may require rapid artificial regeneration depending on the specific climatic (e.g., summer rainy season), geographic (e.g., shallow surface soil and land erosion), and economic (e.g., local mushroom harvesting) objectives. A restoration plan should include constructing fuel breaks to reduce the fire risk if the area is replanted mainly with pine species.

Response of bark beetles and their natural enemies to fire and fire surrogate treatments in mixed-conifer forests in western Montana

Four treatments (control, burn-only, thin-only, and thin-and-burn) were evaluated for their effects on bark beetle-caused mortality in both the short-term (one to four years) and the long-term (seven years) in mixed-conifer forests in western Montana, USA. In addition to assessing bark beetle responses to these treatments, we also measured natural enemy landing rates and resin flow of ponderosa pine (Pinus ponderosa) the season fire treatments were implemented. All bark beetles were present at low population levels (non-outbreak) for the duration of the study. Post-treatment mortality of trees due to bark beetles was lowest in the thin-only and control units and highest in the units receiving burns. Three tree-killing bark beetle species responded positively to fire treatments: Douglas-fir beetle (Dendroctonus pseudotsugae), pine engraver (Ips pini), and western pine beetle (Dendroctonus brevicomis). Red turpentine beetle (Dendroctonus valens) responded positively to fire treatments, but never caused mortality. Three fire damage variables tested (height of crown scorch, percent circumference of the tree bole scorched, or degree of ground char) were significant factors in predicting beetle attack on trees. Douglas-fir beetle and pine engraver responded rapidly to increased availability of resources (fire-damaged trees); however, successful attacks dropped rapidly once these resources were depleted. Movement to green trees by pine engraver was not observed in plots receiving fire treatments, or in thinned plots where slash supported substantial reproduction by this beetle. The fourth tree-killing beetle present at the site, the mountain pine beetle, did not exhibit responses to any treatment. Natural enemies generally arrived at trees the same time as host bark beetles. However, the landing rates of only one, Medetera spp., was affected by treatment. This predator responded positively to thinning treatments. This insect was present in very high numbers indicating a regulatory effect on beetles, at least in the short-term, in thinned stands. Resin flow decreased from June to August. However, resin flow was significantly higher in trees in August than in June in fire treatments. Increased flow in burned trees later in the season did not affect beetle attack success. Overall, responses by beetles to treatments were short-term and limited to fire-damaged trees. Expansions into green trees did not occur. This lack of spread was likely due to a combination of high tree vigor in residual stands and low background populations of bark beetles.

The effect of Sirex noctilio infestation and fire damage on the chemical composition of South African-grown Pinus patula pulpwood

The infection and association between the wood wasp Sirex noctilio and the fungus Amylostereum areolatum is responsible for large-scale tree mortality in the Midlands of the KwaZulu-Natal province in South Africa. An exploratory investigation on the effect of the infestation of trees by the wood wasp and its associated fungus on the chemical composition of Pinus patula pulpwood was undertaken. Various tree classes representing different levels of physiological growth stress from this infestation were compared. Together with the above stress agents, fire damage to P. patula trees was also considered as a possible cause of changes in pulpwood chemical composition. Chemical analyses to determine the Seifert cellulose and Klason lignin contents as well as the levels of water- and solvent-soluble extractives were conducted using published Tappi standard methods. The results indicated only negligible differences between infestation levels (tree classes) with respect to Seifert cellulose and Klason lignin contents. In contrast, highly significant differences were observed for solvent- and water-borne extractives. It is evident from the results that P. patula trees engage a defence strategy to counter the effects of the infestation and the resulting physiological stress. The results of the chemical analyses suggest that trees should not be harvested any younger than the intended rotation age of 12 years and at the time of harvesting all the biomass, including the infected wood, should be sent to the pulp mill. Fire-damaged trees can be utilised in the same way as healthy trees when applying the TMP process provided the charcoal on the outer bark is removed. The usefulness of a biplot to simultaneously display the various tree classes and their chemical composition is illustrated.

Thirty Years of Post-fire Succession in a Southern Boreal Forest Bird Community

Birds and vegetation were surveyed in a 9 ha plot in spring 1976 in a 73 y-old jack pine (Pinus banksiana) – black spruce (Picea mariana) forest in northeastern Minnesota. A 1368 ha wildfire burned across the area that autumn. The plot was resurveyed in 1977 and periodically through 2006. Before the fire, birds with the highest importance values were Blackburnian Warbler (Dendroica fusca), Ovenbird (Seiurus aurocapillus), Red-eyed Vireo (Vireo olivaceus) and Bay-breasted Warbler (D. castanea). Within 7 y following the fire, canopy tree cover decreased to near zero as fire-damaged trees died. Afterwards, the canopy began increasing, reaching 53% cover by 30 y. Shrub cover, 8% before the fire, peaked at over 70% two decades after fire, primarily as a result of dense jack pine and black spruce regeneration, and then decreased to 58% 30 y after fire. The total number of bird species using the area doubled the first year following the fire while the number of bird species with discernable territories decreased 40%. Thereafter, territorial species began increasing and 30 y after the fire the number exceeded the pre-fire richness by 60%. Overall, density of bird territories decreased nearly three-fold the first 3 y after the fire, but by year 30, was over 56% greater than in the pre-burn mature pine forest. Loss of canopy was related to a reduction in warbler and vireo diversity while increases in woody debris and near-ground vegetation were related to an increase in ground-brush foragers such as White-throated Sparrow (Zonotrichia albicollis) and Chipping Sparrow (Spizella passerina). Brown Creeper (Certhia americana) populations increased briefly as trees died, and for five years following fire there was an increase in woodpeckers and secondary cavity nesting species. At 7 to 10 y after fire, White-throated Sparrow, Magnolia Warbler (Dendroica magnolia), Chestnut-sided Warbler (D. pensylvanica), Nashville Warbler (Vermivora ruficapilla) and Mourning Warbler (Oporornis philadelphia) dominated. White-throated Sparrow continued to be the most important bird species through the first two decades, followed by Magnolia Warbler and Red-eyed Vireo. Thirty years after fire, the dominant birds were Nashville Warbler and Ovenbird, followed distantly by Veery (Catharus fuscescens) Swainson's Thrush (Catharus ustulatus), Least Flycatcher (Empidonax minimus) and Black-and-white Warbler (Mniotilta varia). Overall, bird species using the area after 30 y remained over 70% higher than in the mature forest before the fire.

Postfire root distribution of Scots pine in relation to fire behaviour

Fire can potentially have a large direct impact on tree roots and, thus, contribute to reduced vitality. Tree canopy status after fire should have an impact on the postfire production of fine roots, further affecting root function. We analyzed the standing crop of live and dead roots in Pinus sylvestris L. with varying degrees of crown scorch, 1 year after fire in northern Sweden. On the burned sites, total Pinus live fine-root biomass was 74% of that at the control sites, and it was only 19% of the control for roots <2 mm, indicating an 80% reduction due to fire. Root mortality was highest for high-scorch trees, but this was probably due to greater depth of burn in the organic soil for these trees and not to higher fire intensity per se. Fine-root production was also assessed by an ingrowth experiment. This showed relatively similar fine-root production in both control trees and fire-damaged trees, indicating a high allocation to root growth for the damaged trees, to make up for lost root function. Root dynamics after fire are related to a number of factors, and direct effects are determined by the depth of burn in the organic soil layer. Indirect, long-lasting effects could be due mainly to girdling of coarse roots close to tree stems and canopy loss.

Colonization of fire-damaged trees by <i>Ips sexdentatus</i> (Boerner) as related to the percentage of burnt crown

The aim of this study is to determine how bark beetles colonise after a wild fire. Five categories of trees were established according to the percentage of burnt crown (0%, 25%, 50%, 75% and 100%) in a Pinus pinaster forest in León province that had been burnt by awild fire in 1998. During 2000 and 2001 a study was carried out on the percentage of trees attacked in each category, the distribution of attacks on the tree trunk, crown decoloration, number of maternal galleries bored and the number of trees resisting attack. Only 20% of the trees (all of them with 0% unburnt crown) survived the attack. This study shows the capacity of Ips sexdentatus as a primary pest and recommends the removal of dead and dying trees after a wild fire before its population grows large enough to kill the remaining healthy ones.

Attack and Reproductive Success of Mountain Pine Beetles (Coleoptera: Scolytidae) in Fire-Damaged Lodgepole Pines

High-intensity fires are known to kill adult and larval bark beetles, but it is unclear how mountain pine beetles (Dendroctonus ponderosae Hopkins) respond to trees that have been damaged by lower-intensity ground fires at the periphery of burns. We conducted an experiment to determine whether mountain pine beetles preferentially attack trees that have been damaged by fire and to determine how fire damage affects beetles’ reproductive success. We simulated different intensities of ground fires by artificially burning a strip of bark that extended zero-thirds, one-third, two-thirds, or three-thirds around a tree’s circumference. Burn treatments were applied ∼7 wk before beetles emerged from surrounding trees. We found that beetles did not preferentially attack fire-damaged trees; fire damage had no effect on the number of beetles landing on a tree, which trees were attacked, attack rate, attack density, or the body size of beetles attacking a tree. Beetle reproductive success (number and condition of offspring) was also not affected by fire damage. Beetles were more likely to overcome tree defenses and produce successful egg galleries on fire-damaged trees than on undamaged trees, but this was only observed on trees with low beetle attack densities. If beetle attack density was high, trees were successfully attacked irrespective of burn treatment. Our results suggest that fire damage only affects mountain pine beetle reproduction and population growth in areas where attack densities are low. In other situations, fire damage will have negligible effects on beetle attack and reproductive success.

Bark Beetle Attacks on Ponderosa Pine Following Fire in Northern Arizona

Abstract There is little quantitative information on relationships between insect attacks and fire damage for ponderosa pine, Pinus ponderosa Douglas ex Lawson, in the southwestern United States. Tree mortality and insect attacks were measured on 1,367 trees for three years after a spring wildfire (4 May 1996), a summer wildfire (20 June 1996), and a fall prescribed fire (9 September 1995) in northern Arizona. Western pine beetle, Dendroctonus brevicomis LeConte, mountain pine beetle, D. ponderosae Hopkins, roundheaded pine beetle, D. adjunctus Blandford, red turpentine beetle, D. valens LeConte, Ips species, and wood borers in the Buprestidae and Cerambycidae families were found in fire-damaged trees. The most frequently occurring insects, listed from most to least frequent, were wood borers, red turpentine beetle, Ips spp., western pine beetle, roundheaded pine beetle, and mountain pine beetle. Trees attacked by Dendroctonus and Ips spp. as a group had more crown damage from fire than unattacked trees. ...

Ethanol in ponderosa pine as an indicator of physiological injury from fire and its relationship to secondary beetles

Sixteen days after a September wildfire, ethanol and water were measured in phloem and sapwood at breast height and the base of Pinus ponderosa Dougl. ex P. & C. Laws. with zero (control), moderate, heavy, and severe crown scorch. The quantity of ethanol increased with each level of injury, resulting in trees with severe scorch containing 15 and 53 times more phloem and sapwood ethanol, respectively, than controls. Ethanol concentrations in the sapwood and adjacent phloem were related, probably as a result of diffusion. Upward movement in xylem sap was most likely responsible for the relationship between sapwood ethanol concentrations at breast height and the stem base. As trees recovered from their heat injuries, the ethanol concentrations declined. In contrast, ethanol accumulated in dead trees that lost their entire crowns in the fire. Various bark and xylophagous beetles landed in greater numbers on fire-damaged trees than on controls the following spring and summer, suggesting that ethanol was being released to the atmosphere and influencing beetle behavior. Beetle landing was more strongly related to sapwood ethanol concentrations the previous September than in May. Sapwood ethanol measured 16 days after the fire was the best predictor of second-year mortality for trees with heavy and severe crown scorch.

Managing attack by bark and ambrosia beetles (Coleoptera: Scolytidae) in fire-damaged Pinus plantations and salvaged logs in Queensland, Australia

Summary In late 1994, bushfires in the Beerburrum area north of Brisbane, in Queensland, Australia, damaged 8688 hectares of pine plantations (mostly Pinus elliotlii, P. caribaea and P. taeda). In the 4712 hectares of government-owned plantations affected, large-scale salvage operations were commenced quickly in order to minimise damage by the established exotic bark beetle Ips grandicollis Eichhoff and associated sapstaining fungi. The bark beetle began attacking fire-damaged trees 6 weeks after the fire and was significant in most areas at 10 weeks. Sapstain carried by I. grandicollis became significant at the completion of a life cycle of the insect (about 4 weeks in summer). Losses caused by I. grandicollis and sapstain following the fire were estimated at several million dollars Australian, mostly in privately-owned plantations where salvage was delayed for several months. Salvaged timber was stored on a 49 hectare site at Beerburrum under water spray to inhibit degrade of logs by insects and fungi. Serious attack of the logs by the ambrosia beetles Xyleborus perforans (Wollaston) and Xyleborus ferrugineus (Fabricius) occurred one year after the storage commenced, and a high incidence of the decay fungus Rigidoporus lineatus (Pers.) Ryvarden was also detected in stored logs at that time. The circumstances associated with the insect attack, management options and implications for contingency planning are discussed in this paper. The main recommendations are to salvage all material within three months and store under water spray for periods no longer than six months.

Sapstain and decay following fire in stands of Pinus elliottii var. elliottii near Beerburrum, south east Queensland

Summary In September and November, 1994, wildfires caused damage to 9 thousand hectares of slash pine (Pinus elliottii var. elliottii) in plantations near Beerburrum in south east Queensland. During the salvage operation sapstain and decay were monitored by periodically felling and sectioning trees in five plots in stands damaged by the November fire. Appreciable bluestain (affecting more than 10% of stem wood per plot) was first observed 10–13 weeks after the fire. Bluestain was associated with attack by the introduced bark beetle Ips grandicollis. and was initially greatest in plots where the earliest insect attack occurred. Bluestain was also dependant on moisture content and was significant where mean values fell below 100–110%, as drying occurred particularly in the outer sapwood. Trees with severe crown scorch dried more rapidly and developed substantial bluestain more quickly, except towards the base of the stem. Where less severely damaged, the sapwood of green-crowned trees dried gradually and developed bluestain more slowly, but even green-crowned trees attacked by I. grandicollis eventually became substantially bluestained. In a supplementary study in a plantation of slash pine on Bribie Island damaged in the November fire, bluestain was found only in association with attack by Ips grandicollis, which was a reliable indicator of the presence of stain in fire-damaged stands. Isolations from the bluestained sapwood regularly yielded a species of Ophiostoma apparently introduced to the fire-damaged trees by Ips grandicollis. Sphaeropsis sapinea was not isolated from stems, but was present in dry branches and remains a potential agent of bluestain under suitable conditions. Signs of decay fungi were first detected 21 weeks after the fire, and decay was identified in 71% of the study trees sampled after 49 weeks. Stands appreciably damaged in early summer fires in south east Queensland should be salvaged within 3 months to avoid significant bluestain.

Insects in burned forests - forest protection and faunal conservation (preliminary results)

The beetle colonization of fire-damaged trees was studied in seven reserves, which were established in burned forests in south and central Sweden, following extensive forest fires in the summer of 1992. In the spring of 1993, burned pine trees displayed a large range in fire damage from virtually undamaged ones to trees killed by the fire. Spruces were more sensitive than pine, and few fire-damaged spruces had some green foliage left. The pine shoot beetle, Tomicus piniperda (Linnaeus) was the main colonizer of pine trees, occurring at all sites, but altogether in only one-third of the trees. On spruce, two bark beetles were common: Polygraphus poligraphus (Linnaeus) was found on nearly all sites and altogether on half of the trees, followed in abundance by Pityogenes chalcographus (Linnaeus). These common species were accompaniedby an assembly of bark and longhorn beetles, commonly occurring on fresh conifer timber. Most of the beetle species clearly preferred the dead or dying trees. However, the species mentioned above as well as Arhopalus rusticus (Linnaeus) also attacked trees with more than half of the foliage left. Three fire-favoured species were observed: Oxypteris (Melanophila) acuminata (Degeer), Sericoda (Agonum) quadripunctata (Degeer) and Pterostichus quadrifoveolatus (Letzner). Line surveys indicated little bark beetle dispersal from the burned areas into surrounding forests. Further studies are needed as the primary colonization of the burned trees was obviously not completed during this first year after the fire.