Survival Of Pine Research Articles

Effects of brassinosteroids on prosperity of Scots pine seedlings

We tested the influence of exogenous application of brassinosteroids (BRs) on survival, growth and biomass production of Scots pine (Pinus sylvestris) seedlings. BRs are natural substances, supposedly having many positive effects on plants such as improving growth, stress tolerance, survival and biomass production. One part of the seedlings was treated with a low concentration of synthetically prepared BRs and the other part was designated as the control without any treatment. Mortality, height and root collar diameter were measured in two subsequent years, the root-to-shoot ratio of biomass volume was determined in autumn 2013. The application of BRs significantly slowed height and radial growth of pine. The height increment of the BRs-treated seedlings was lower by 11% between 2012 and 2013 compared to the control. The increment in root collar diameter (2012–2013) in the BRs-treated seedlings was lower by 13% than in the control. The BRs-treated pines also experienced a significantly higher mortality compared to the control. No significant influence of BRs on biomass production was found.  

The influence of initial spacing on growth and survival of Scots pine in 40 years period of cultivation in varied habitat conditions

Abstract The aim of the research was to determine the effect of initial spacing on the survival and growth of pine trees in dry coniferous and fresh coniferous forest habitats after nearly 40 years from the establishment of plantation. The study presents an analysis of seven spacing variants in square, rectangular and triangular spacing patterns with the initial density ranging from 6 944 seedlings/ha to 15 625 seedlings/ha. The studies were conducted on two study sites. No tending treatments (selective thinning) were performed in the examined stands throughout the growing season. It was shown that habitat conditions had a significant effect on the survival, diameter and height growth of trees in pine stands. In the less productive forest habitat, where the competition of trees is smaller, the survival was 1.5 to 2-fold higher compared to the more productive habitat. Pine trees growing in the fresh coniferous forest had substantially larger diameters at breast height (dbh) compared to the dry coniferous forest. The spacing effect depended on the habitat conditions. This influence was stronger in the less productive habitat compared to the more productive forest habitat which was reflected in the greater differences in the discussed parameters. The average dbh value of all trees on the Płock site increased with the increase of tree growing space (i.e. lower initial planting density) and ranged from 8.24 cm in variant A (15 625 seedlings/ha) to 9.79 cm in variant C (6 944 seedlings/ha). On the Łąck site, the trees growing at a low density (variants C and E) had significantly larger diameters compared to the trees growing at a density from 10 000 plants/ha to 15 625 plants/ha (spacing variants A, B, F, G). The studies also showed a significant effect of the habitat conditions and initial spacing on the diameter of pine trees in biosocial class I. Triangular spacing in the fresh coniferous forest was found to have more positive effect on tree diameter growth. It is consistent with the findings of other authors that trees planted in triangular spacing make better use of space which is positively reflected in their growth. The results obtained from the research allow to formulate the conclusion that habitat conditions have a significant effect on the survival, diameter and height growth of trees in pine stands. The research also showed a significant effect of initial spacing on the diameter at breast height of pines at the end of age class II. No dependence was found of the initial planting density on the height growth rate of trees. In both forest habitats under consideration, trees planted at a density of approximately 11.5 thousand plants per hectare were the highest. The triangular initial spacing pattern had a positive effect on this characteristic.

Neighborhood analysis of underplanted Korean pine demography in larch plantations: Implications for uneven-aged management in northeast China

Quantifying the growth and survival of underplanted Korean pine (Pinus koraiensis Sieb. et Zucc.) in existing plantations provides a critical step toward developing an uneven-aged management system in northeast China. We conducted neighborhood analysis to quantify the effect of individual-level competition on the growth and survival of underplanted Korean pines in larch plantations (Larix olgensis A. Henry and Larix kaempferi [Lamb.] Carr.). The growth rate depended significantly on target tree size and the strength of competition from neighboring trees, whereas survival depended solely on tree size. The survival rate increased sharply with increasing tree size, and trees that had reached ca. 3cm in diameter at a height of 0.3m rarely died, even under strong competition. The effect of competition from neighbors on growth was determined by the neighboring tree’s size and its spatial relationship with the target tree. Neighbors located near and southwest of the target tree produced stronger competition than trees at greater distances and different azimuths. Our simulation in which Korean pines were underplanted in strip openings showed that their growth rates increased with increasing strip width. The growth rate was also related to the strip’s azimuth and the underplanting position within the opening. The results indicate that planting Korean pines in northwest to southeast strips would create a more heterogeneous size structure than planting in northeast to southwest strips. Our results suggest that spatial factors such as strip width, strip direction, and planting position strongly influence the development and productivity of uneven-aged Korean pine–larch stands.

White Pine Restoration in a Mesic Forest: 3-year Results

Abstract Pinus strobus (Eastern White Pine) was an important component of mesic and dry-mesic northern temperate forests prior to European settlement. We evaluated the efficacy of restoration on a degraded, mesic hardwood site with a low post-harvest residual basal area (11.5 m2 ha-1). Three-year survival of planted pines was 57% (n = 299), with 40% mortality occurring the first year. Additional losses, however, were minimal: 2% and 1%) following years two and three, respectively. Survival was associated with presence of bare soil near the seedling (P < 0.05). High initial mortality was likely attributable to drought. Our results suggest that White Pine establishment on more mesic hardwood sites may be possible given sufficient soil and canopy disturbance, but that high initial mortality may be expected under dry climatic conditions.

Dendrochronological Assessment of Whitebark Pine Response to Past Climate Change: Implications for a Threatened Species in Grand Teton National Park

One of the keystone tree species in subalpine forests of the western United States – whitebark pine (Pinus albicaulis, hereafter whitebark pine) – is experiencing a significant mortality event (Millar et al. 2012). Whitebark pine occupies a relatively restricted range in the high-elevation ecosystems in the northern Rockies and its future is uncertain. The current decline of whitebark pine populations has been attributed to pine beetle infestations, blister rust infections, anthropogenic fire suppression, and climate change (Millar et al. 2012). Despite the knowledge that whitebark pine is severely threatened by multiple stressors, little is known about the historic capacity of this species to handle these stressors. More specifically, it is unknown how whitebark pine has dealt with past climatic variability, particularly variation in the type of precipitation (rain vs. snow) available for soil moisture, and how differences in quantity of precipitation have influenced the establishment and growth of modern stands. We propose to study the past responses of whitebark pine to paleoclimatic conditions, which would be useful to park ecologists in developing new conservation and regeneration plans to prevent the extinction of this already severely threatened high-elevation resource. The purpose of this study is to determine in great temporal and spatial detail the demographics of the current stand of whitebark pine trees in the watershed surrounding an unnamed, high-altitude pond (known informally as Whitebark Pine Moraine Pond) located approximately 3.06 miles NW of Jenny Lake in Grand Teton National Park (GTNP). The main objectives of this study were: 1.) To obtain the precise GPS locations of the current stand of whitebark pine trees in the watershed to generate a GIS map detailing their locations. 2.) To obtain increment cores of a subset of the trees in the watershed to estimate age and date of establishment for the current stand of whitebark pines, with particular attention to fire history. 3.) To analyze ring widths from core samples to identify climatic indicators that may influence the regeneration and survival of whitebark pine.

An integrated model of environmental effects on growth, carbohydrate balance, and mortality of Pinus ponderosa forests in the southern Rocky Mountains.

Climate-induced tree mortality is an increasing concern for forest managers around the world. We used a coupled hydrologic and ecosystem carbon cycling model to assess temperature and precipitation impacts on productivity and survival of ponderosa pine (Pinus ponderosa). Model predictions were evaluated using observations of productivity and survival for three ponderosa pine stands located across an 800 m elevation gradient in the southern Rocky Mountains, USA, during a 10-year period that ended in a severe drought and extensive tree mortality at the lowest elevation site. We demonstrate the utility of a relatively simple representation of declines in non-structural carbohydrate (NSC) as an approach for estimating patterns of ponderosa pine vulnerability to drought and the likelihood of survival along an elevation gradient. We assess the sensitivity of simulated net primary production, NSC storage dynamics, and mortality to site climate and soil characteristics as well as uncertainty in the allocation of carbon to the NSC pool. For a fairly wide set of assumptions, the model estimates captured elevational gradients and temporal patterns in growth and biomass. Model results that best predict mortality risk also yield productivity, leaf area, and biomass estimates that are qualitatively consistent with observations across the sites. Using this constrained set of parameters, we found that productivity and likelihood of survival were equally dependent on elevation-driven variation in temperature and precipitation. Our results demonstrate the potential for a coupled hydrology-ecosystem carbon cycling model that includes a simple model of NSC dynamics to predict drought-related mortality. Given that increases in temperature and in the frequency and severity of drought are predicted for a broad range of ponderosa pine and other western North America conifer forest habitats, the model potentially has broad utility for assessing ecosystem vulnerabilities.

Effects of Herbaceous and Woody Plant Control on Longleaf Pine Growth and Understory Plant Cover

To determine if either herbaceous or woody plants are more competitive with longleaf pine (Pinus palustris Mill.) trees, four vegetation management treatments—check, herbaceous plant control (HPC), woody plant control (WPC), and HPC+WPC—were applied in newly established longleaf pine plantings in a randomized complete block design in two studies. Prescribed fire was repeatedly applied across both study sites, and pine measurements were continued for 12 years. Pine survival was not significantly different among the four treatments in either study. In Study 1, pines were taller on HPC+WPC plots than on checks, and pine basal area and volume per ha were greater on HPC and HPC+WPC plots than on checks. Volume per ha ranged from 45 m3/ha on checks to 70 m3/ha on HPC+WPC plots. The WPC treatment was ineffective. In Study 2, there were no significant basal area and volume per ha differences among the four treatments. Volume per ha ranged from 119 m3/ha on checks to 151 m3/ha on HPC+WPC plots after 12 years. In the thirteenth growing season, HPC+WPC plots had more surface area covered in litter than did checks, and there was less grass cover on HPC plots than on checks in Study 1. In Study 2, litter and plant cover in the understory were not significantly different among the four treatments. With the application of fire, HPC remained effective when basal area per ha did not exceed 14 m2/ha. WPC was not beneficial perhaps because prescribed fire was repeatedly applied making WPC unnecessary.

Identities and distributions of the co-invading ectomycorrhizal fungal symbionts of exotic pines in the Hawaiian Islands

Pine species have become invasive throughout the globe and threaten to replace native biota. The threat of pine invasion is particularly pressing in parts of the tropics where there are no native pines. The factors that govern pine invasion are not often well understood. However, key to pine survival is an obligate and mutualistic interaction with ectomycorrhizal fungi. Thus for pines to successfully invade new habitats compatible ectomycorrhizal fungi must already be present, or be co-introduced. The purpose of this study was to examine the community structure of non-native ectomycorrhizal fungi associated with pine invasions in the Hawaiian Islands. To accomplish this we executed a field and greenhouse study and used a molecular ecology approach to identify the fungi associating with invasive pines in Hawai‘i. We show that: (1) ectomycorrhizal fungal species richness in non-native pine plantations is far less than what is found in pine’s native range, (2) there was a significant decrease in average ectomycorrhizal fungal species richness as distance from pine plantations increased and, (3) Suillus species were the dominant fungi colonizing pines outside plantations. The keystone ectomycorrhizal fungal taxa responsible for pine establishment in Hawai‘i are within genera commonly associated with pine invasions throughout the globe. We surmise that these fungi share functional traits such as the ability for long-distance dispersal from plantations and host tree colonization via spore that lead to their success when introduced to new habitats.

Fellingas a Pre-Treatment for Prescribed Fire Promotes Restoration of Fire-Suppressed Florida Sandhill

ABSTRACT: Fire suppression in sandhill ecosystems leads to biotic impoverishment and reduces fine fuels needed for frequent fires. We investigated the restoration dynamics of a long-unburned endemic-rich sandhill on Florida's Lake Wales Ridge using prescribed fire with and without prior chainsaw felling of the hardwood subcanopy. Our goals were to promote survival of longleaf pines (Pinus palustris), decrease subcanopy and shrub densities and lichen cover, and increase cover of graminoids and rare forbs. Treatments were applied in 2001 and responses monitored annually through 2005. Prior felling of the subcanopy increased fire temperatures, residence times, and coverage compared to the burn-only treatment. The saw and burn treatment was effective in removing the subcanopy, but caused an undesirable increase in longleaf pine mortality. Pine mortality decreased with distance from saw and burn plots. Post-treatment shrub densities initially decreased, then increased in both treatments relative to controls. F...

Recovery from topkill of shortleaf pine × loblolly pine hybrids compared to their parent populations

Hybrids between shortleaf pine (Pinus echinata Mill.) and loblolly pine (Pinus taeda L.) have increased since the 1950s throughout the southeastern USA. Previously, greater sprouting capacity and the formation of a basal crook that lowers the height of dormant buds may have favored pure shortleaf pine populations on fire prone sites. The objective of this study was to determine how seasonal timing of topkill by both fire and topclipping affect sprouting of shortleaf × loblolly pine F1 hybrids compared to their parent open-pollinated populations during their third growing season. A factorial combination of top-clipping (hand pruners) and girdling by fire (propane torch) was conducted on November 2010, January, March, and April 2011 and sprouting response was measured after the growing season. Survival of topkilled shortleaf pine (94 %) was greatest followed by hybrid (78 %) and loblolly pine (35 %). However, species effects varied with topkill treatment and treatment date because survival was relatively lower for loblolly and hybrid pines in the burn-only as well as the November and April treatment dates while survival of shortleaf pine was consistently high. The number of sprouts was greatest for shortleaf (32.3) intermediate for hybrid (23.8) and lowest for loblolly pine (12.0). Overall, 83 % of shortleaf pine, 35 % of hybrid pine, and 5 % of loblolly pine exhibited a basal crook. The height from ground line to the lowest sprout was shortest for shortleaf (3.5 mm), intermediate for hybrids (7.7 mm), and largest for loblolly pine (21.3 mm). While the hybrid saplings exhibited intermediate performance in survival, sprouting capacity, and crooking, pure shortleaf pine were superior and are probably better suited to recover from fire.

The Role of Dendrochronology in Understanding the Modern Decline of Whitebark Pine in Grand Teton National Park, Wyoming

Whitebark pine (Pinus albicaulis) is the only pine keystone species found in North America. Although it is considered a keystone species in high elevation ecosystems in the northern Rockies, it occupies a relatively restricted range and its future is uncertain. In modern times, it has experienced a significant decline in population due to pine beetle infestations, blister rust infections, fire suppression, and climate change. Despite the knowledge that the species is severely threatened, little is known about its paleoecology. More specifically, much remains unknown about how the distribution and stability of whitebark pine were affected by past climate change. The purpose of this study is to determine in great temporal and spatial detail the demographics of the current stand of whitebark pine trees in the watershed surrounding an unnamed, high-altitude pond (known informally as Whitebark Pine Moraine Pond) located approximately 3.06 miles NW of Jenny Lake in Grand Teton National Park (GTNP). The main objectives of this study are: 1.) To obtain the precise GPS locations of the current stand of whitebark pine trees in the watershed to generate a GIS map detailing their locations. 2.) To obtain increment cores of a subset of the trees in the watershed to estimate age and date of establishment for the current stand of whitebark pines, with particular attention to fire history. 3.) To analyze ring widths from core samples to identify climatic indicators that may influence the regeneration and survival of whitebark pine.

Glacial to paraglacial history and forest recovery in the Oglio glacier system (Italian Alps) between 26 and 15 ka cal BP

The integrated stratigraphic, radiocarbon and palynological record from an end-moraine system of the Oglio valley glacier (Italian Alps), propagating a lobe upstream in a lateral reach, provided evidence for a complete cycle of glacial advance, culmination and withdrawal during the Last Glacial Maximum and early Lateglacial. The glacier culminated in the end moraine shortly after 25.8 ± 0.8 ka cal BP, and cleared the valley floor 18.3–17.2 ± 0.3 ka cal BP. A primary paraglacial phase is then recorded by fast progradation of the valley floor.As early as 16.7 ± 0.3 ka cal BP, early stabilization of alluvial fans and lake filling promoted expansion of cembran pine. This is an unprecedented evidence of direct tree response to depletion of paraglacial activity during the early Lateglacial, and also documents the cembran pine survival in the mountain belt of the Italian Alps during the last glaciation. Between 16.1 and 14.6 ± 0.5 ka cal BP, debris cones emplacement points to a moisture increase favouring tree Betula and Pinus sylvestris-mugo. A climate perturbation renewed paraglacial activity. According to cosmogenic ages on glacial deposits and AMS radiocarbon ages from lake records in South-Eastern Alps such phase compares favourably with the Gschnitz stadial and with the oscillations recorded at lakes Ragogna, Längsee and Jeserzersee, most probably forced by the latest freshening phases of the Heinrich Event 1.A further sharp pine rise marks the subsequent onset of Bølling interstadial.The chronology of the Oglio glacier compares closely with major piedmont glaciers on the Central and Eastern Alpine forelands. On the other hand, the results of the present study imply a chronostratigraphic re-assessment of the recent geological mapping of the Central Italian Alps.

Planting Deep Increases Early Survival and Growth of Pinus echinata Seedlings

Two studies were established to determine the effects of planting depth on early performance of bareroot shortleaf pine seedlings (Pinus echinata). The studies involved planting seedlings either with the root-collar slightly below the groundline (GL) or with the root-collar planted about 11 cm below the soil surface (DEEP). After transplanting, DEEP seedlings had about 7.9 cm of shoot remaining aboveground. In one study, seedlings were planted in open sand pits where seedlings received 352 mm of rain by April 30. The second study involved planting seedlings in boxes (containing sand) in a roofed shade-house. Without rain, survival of DEEP seedlings in April was 96% which was significantly greater (P>F =0.007) than survival of GL seedlings (67%). With rainfall, survival (95%) was the same for both planting depths (P>F = 0.39). Therefore, planting seedlings with the root-collar level with the soil surface can, in some years, increase mortality. This might help explain why bareroot survival of shortleaf pine in some forest districts averages less than 80%.

Growth, survival, and genetic variability of Austrian pine (Pinus nigra Arnold) seedlings in response to water deficit

Drought is one of the crucial factors limiting plant growth and is expected to become even more limiting in many regions as the effects of climate change increase. Knowledge of genetic adaptation to environmental factors can help develop strategies for successful reforestation in arid terrain. In this study, Austrian pine (Pinus nigra Arnold) seedlings grown from seed collected from 40 open-pollinated families from five Balkan Peninsula provenances were evaluated for survival and growth under imposed drought. Within each provenance, seed was collected from an extremely harsh habitat and from a favorable habitat. One-year-old seedlings, from each provenance, habitat type and open pollinated family were transplanted into three “stressbeds”, each designed to simulate different levels of water availability by filling with varying ratios of crushed stone and soil. Seedling height growth and survival were recorded every 20–30 days from April–September. In all provenances, seedlings grown from seed originating from the harsh habitats had lower survival regardless of stressbed treatment compared to those grown from seed collected from favorable habitats, with the exception of one population from the Visegrad provenance which had high survival rates throughout. Overall height growth was very low and did not follow consistent patterns among treatment groups. Cluster analyses of survival data showed that populations from a similar habitat generally grouped together, regardless of provenance. The lowest and highest survival values were found in seedlings from harsh habitats, while those from the favorable habitats clustered in the mid-range. These results suggest that higher seed quality from productive stands may be the most influential factor determining seedling vigor under drought stress and that genetic adaptation to drought was not detected in adjacent populations having different habitat conditions.

Pythium species and cold storage affect the root growth potential and survival of loblolly (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) seedlings

When bareroot Southern pine (Pinus) seedlings are lifted in the fall and placed in cold storage for more than one week, survival is generally lower than when seedlings are lifted and stored during the winter. The combination of root wounding at the time of lifting with the presence of Pythium in the soil, the cool, moist conditions in cold storage encourage Pythium growth that results in seedling mortality after outplanting. Loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) seedlings were inoculated with either Pythium dimorphum orPythium irregulare, cold stored for 3 weeks, and placed in a hydroponic system (aerated aquariums). Seedling Root growth potential (RGP was measured as the number, length, volume, surface area, and diameter of new roots and survival was recorded 4 months after outplanting. Both Pythium species reduced the number of new roots and root length, root surface area, and root volume in slash pine. P. irregulare reduced the number of new roots, root length, and root surface area andP. dimorphum reduced the number of new roots on loblolly pine. Although, P. irregulare lowered RGP, it did not reduce loblolly pine survival. In contrast, P. irregulare inoculation did reduce the survival of slash pine seedlings after outplanting. Key words: Pythium dimorphum, Pythium irregular, root collar diameter; bareroot.

Effects of Pythium Species and Time in Cold Storage on the Survival of Bareroot and Container-Grown Southern Pine Seedlings

Cold storing bareroot southern pine (Pinus spp.) seedlings for greater than one week after lifting in the fall can lead to poor outplanting survival when compared to seedlings that are lifted and stored in winter. In contrast, container-grown seedlings typically do not experience adverse effects from storing for periods greater than one week. The practice of lifting bareroot seedlings can cause wounds to root systems, which could allow soil-borne pathogens such as Pythium species to be used as infection sites. Once seedlings are placed in storage, the cool, moist environment may be conducive for zoospore activity, leading to root disease and outplanting failure. Bareroot and container-grown longleaf pine (Pinus palustris), loblolly pine (Pinus taeda), and slash pine (Pinus elliottii) and container-grown shortleaf pine (Pinus echinata) were inoculated with either Pythium dimorphum or Pythium irregulare, cold-stored for 3, 4, 6, or 12 weeks, and outplanted. Both Pythium species reduced survival of bareroot longleaf pine but not bareroot slash pine. Length of storage decreased survival for both seedling stock types. Pythium species did not affect the survival of container-grown seedlings. These results suggest that P. dimorphum and P. irregulare are more virulent to bareroot longleaf pine than the other pine species tested.

Deep Planting Has No Short- or Long-Term Effect on the Survival and Growth of White Spruce, Black Spruce, and Jack Pine

Abstract Although studies in the past have reported that the deeper planting of conifers has no effect on seedling performance, most planting guidelines in use today still recommend that seedlings be planted to the rootcollar. Past studies were mostly observational, used bareroot seedlings, and often reported early results from just one or two depths of planting treatments. Most of the results available regarding planting depth for boreal species are anecdotal, although they are planted by the hundreds of millions every year. The present study reports no short-term (1 year) or long-term (15 to 19 years) negative effect of planting depth on the survival and height and diameter growth of black spruce, white spruce, and jack pine seedlings over three large, replicated experiments in the boreal forest of eastern and northern Quebec (eastern Canada). Four different depth treatments were compared, from manual planting at the rootcollar to the deepest mechanical planting treatment at 10 cm or more, making this the largest, longest-lasting study of its kind. Although, as expected, important differences in growth were present between species, all three commonly planted conifers reacted similarly to the planting depth treatments (no effect). This result can in part be attributed to an almost perfect control of frost heaving in the deepest two treatments. Planting depth effects were assessed using analysis of variance, multiple Tukey honestly significant difference, and uncorrected pairwise one-tailed t-tests to increase the probability of detecting a negative effect. Absolute differences and effect sizes (generally small and often positive with greater depths) were also analyzed.

Mortality of urban pines in Helsinki explored using tree rings and climate records

The mortality of Scots pine trees in and around Helsinki has been reported in recent years, but the causalities of these deaths have not so far been rigorously examined. Tree-ring analyses have previously shown to effectively reveal historical growth variability and thus hint at the stress factors behind tree mortality. Here, we analyzed the tree rings of pines in two tree classes (living and dead) from an urban park in Helsinki to reveal their growth variations and to examine the obtained chronologies along with climatic data. Guided by tree-ring information, the pine growth over the past century could be divided into four episodes: average growth conditions during the first half of the twentieth century, a suppressed growth period during the 1950s and 1960s, a growth release since the mid-1970s, and a period of recent mortality. The two tree classes became particularly differentiated during the release period in that the growth of surviving pines underwent a more positive and abrupt growth anomaly in comparison to dead pines. The survival of pines could also be linked to their sensitivity to droughts in a long-term context: The growth of still-living pines showed a statistically significant moisture sensitivity over the second half of the century only. The period 2002–2003 (coinciding with drought) was observed as a dendrochronologically dated episode with a 40% mortality. Overall, the results point to the importance of tree competitive strength and climate as predisposing and inciting/contributing factors behind the tree mortality.

Survival of southern pine seedlings after inoculations with Pythium and cold storage in the presence of peat moss

SummaryCold storing bareroot pine (Pinus spp.) seedlings grown in the southern U.S. for as little as 1 week in a cooler (just above freezing) in the fall (November to mid‐December) has been shown to reduce seedling survival after outplanting. In contrast, survival of container‐grown seedling is typically not affected when stored for 4 weeks in coolers in November and December. Wounds sustained by seedlings as they are lifted from nursery beds may allow Pythium spp. to infect bareroot seedling roots. Once in the cool, moist storage environment, Pythium multiplies and may result in seedling mortality after outplanting. Bareroot loblolly pine (Pinus taeda) and container‐grown loblolly, longleaf (Pinus palustris), slash (Pinus elliottii) and shortleaf pine (Pinus echinata) seedlings were inoculated with either Pythium dimorphum or Pythium irregulare, cold stored with or without peat moss and monitored for survival after outplanting. Peat moss did not increase bareroot loblolly pine survival or reduce Pythium populations when seedlings were inoculated with Pythium prior to storage. Pythium irregulare reduced survival of longleaf and shortleaf pine grown in peat moss and perlite, respectively. Pythium did not affect loblolly or slash pine, but wounding their roots did reduce seedling survival when grown in containers.

Ecosystem, Location, and Climate Effects on Foliar Secondary Metabolites of Lodgepole Pine Populations from Central British Columbia

Lodgepole pines, Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson, are encountering increased abiotic stress and pest activity due to recent increases in temperature and changes in precipitation throughout their range. This tree species counters these threats by producing secondary metabolites, including phenolics and terpenoids. We examined foliar levels of lignin, soluble phenolics, monoterpenoids, sesquiterpenoids, and diterpenoids in 12 stands in British Columbia, Canada. We used these data to assess associations among foliar secondary metabolite levels and ecosystem, geographic, and climatic variables. Regressions were also performed to observe which combinations of variables best explained secondary metabolite variance. Stands of P. c. latifolia in the Coastal Western Hemlock and Interior Cedar/Hemlock biogeoclimatic zones had consistently greater foliar levels of almost all measured secondary metabolites than did other stands. Lignin was present in greater amounts in Boreal White/Black Spruce ecosystem (i.e., northern) stands than in southern stands, suggesting a role for this metabolite in pine survival in the boreal forest. Attempts to develop regression models with geographic and climatic variables to explain foliar secondary metabolite levels resulted in multiple models with similar predictive capability. Since foliar secondary metabolite levels appeared to vary most between stand ecosystem types and not as much due to geographic and climatic variables, metabolic profiles appeared best matched to the stress levels within local environments. It is unknown if differences in secondary metabolite levels are the result of genetic adaptation or phenotypic plasticity, but results from this and other studies suggest that both are important. These results are interpreted in light of ongoing efforts to assist in the migration of certain populations of P. c. latifolia northward in an effort to counter predicted effects of climate change.