Red Pine Research Articles

Effect of Plant Diversity on the Occurrence of Diplodia Tip Blight in Natural Secondary Japanese Red Pine Forests

Diplodia tip blight caused by Sphaeropsis sapinea (Fr.) Dyko and B. Sutton is a serious threat to the health of natural secondary Japanese red pine (Pinus densiflora Sieb. et Zucc.) forests. To explore the effect of plant diversity on Diplodia tip blight disease occurrence, the correlation between Diplodia tip blight in P. densiflora and plant diversity in various stand types and vertical structure layers were analyzed by Pearson correlation coefficients and generalized linear model while keeping environmental factors relatively consistent. Disease index of Diplodia tip blight in P. densiflora was positively correlated with the plant diversity indices in the tree layers of P. densiflora–conifer mixed forest. In contrast, it was negatively correlated with the plant diversity indices in the tree layers of P. densiflora–hardwood mixed forest and P. densiflora pure forest. In shrub–herb layers of all stands except the P. densiflora pure forest herb layer, the disease index was positively correlated with the plant diversity indices. The prediction models for the disease index of Diplodia tip blight in the P. densiflora–hardwood mixed forest, P. densiflora–conifer mixed forest, and P. densiflora pure forest were also established. The foregoing results suggest that in the Kunyu Mountains of China, the differences in plant diversity among various stand types and vertical structure layers have different effects on the occurrence of Diplodia tip blight in P. densiflora. Plant diversity largely reflects the occurrence of Diplodia tip blight disease. However, if the effect of plant diversity on Diplodia tip blight is fully reflected, the plant species characteristics, especially tree genetic relationships, should be considered. In this way, plant species diversity structure in natural secondary Japanese red pine forests may be modified through forest management to lower the incidence of Diplodia tip blight.

Herrings, High-Rises, and Hongeo

Herrings, High-Rises, and <i>Hongeo</i>

Historical fire regimes of North American hemiboreal peatlands

Peatlands contain one-third to one-half of global soil carbon, and disturbances, specifically fire, directly influence these carbon stocks. Despite this, historical variability of peatland fire regimes is largely unknown. This gap in knowledge partly stems from reconstructions of peatland fire regimes with methods limited to evaluating infrequent, severe fire events and not capturing frequent, low-severity events. Furthermore, variability in fire regimes is likely higher in heterogenous landscapes like the hemiboreal subzone, the transition between boreal and temperate biomes, where peatlands are embedded in landscapes including forests with high proportions of fire-dependent species, such as red pine (Pinus resinosa), that are well adapted to frequent low-severity fires. Here, we sought to evaluate the role of low- and moderate-severity fires within hemiboreal peatlands in central North America to better understand historical variability in fire regimes. We reconstructed historical fire regimes using fine-scale (temporal and spatial) dendrochronology methods to estimate frequency of low- and moderate-severity fires, identify synchronous fire events among forested uplands within and surrounding individual peatlands as well as among sites, and assess fire-climate relationships. We collected 220 cross-sections or partial-tree sections within three poor fen peatlands across the Great Lakes Region. Using standard dendrochronological techniques, we crossdated 129 samples, assigning dates to 414 fire scars (128 unique fire years) comprising a 500-year tree-ring record (1520–2019). Prior to the mid-1900s, fire events were frequent and widespread within peatlands we evaluated, with mean fire return intervals (MFRI) ranging from 7 to 31 years. Fire events were also synchronous among forested uplands within and surrounding peatlands. Fires predominantly occurred in the dormant and latewood (growing season) positions and during regionally dry conditions corresponding to mild and moderate drought (Palmer Drought Severity Index ≥ −2.99) but interestingly not during regionally severe drought (Palmer Drought Severity Index ≤ −3.00). While large-scale, high-severity fires are important to the ecology of peatlands and to changing climate-fire interactions, our results suggest that widespread low- to moderate-severity fires were historically frequent in hemiboreal peatlands and likely central to their development and maintenance. Evaluating whether peatlands will continue to be carbon sinks or become carbon sources due to climate change requires an understanding of the inherent variability in fire regimes, especially in hemiboreal systems.

Neuroprotective and Anti-Inflammatory Effects of Pinus densiflora Bark Extract in Gerbil Hippocampus Following Transient Forebrain Ischemia.

Korean red pine (Pinus densiflora) belongs to the Genus Pinus, and its bark contains a great amount of naturally occurring phenolic compounds. Until now, few studies have been conducted to assess the neuroprotective effects of Pinus densiflora bark extract against brain ischemic injury. The aim of this study was to investigate the neuroprotective effects of pre-treatment with the extract in the hippocampus following 5-min transient forebrain ischemia in gerbils. Furthermore, this study examined the anti-inflammatory effect as a neuroprotective mechanism of the extract. Pinus densiflora bark was extracted by pure water (100 °C), and this extract was quantitatively analyzed and contained abundant polyphenols, flavonoids, and proanthocyanidins. The extract (25, 50, and 100 mg/kg) was orally administered once a day for seven days before the ischemia. In the gerbil hippocampus, death of the pyramidal neurons was found in the subfield cornu ammonis 1 (CA1) five days after the ischemia. This death was significantly attenuated by pre-treatment with 100 mg/kg, not 25 or 50 mg/kg, of the extract. The treatment with 100 mg/kg of the extract markedly inhibited the activation of microglia (microgliosis) and significantly decreased the expression of pro-inflammatory cytokines (interleukin 1β and tumor necrosis factor α). In addition, the treatment significantly increased anti-inflammatory cytokines (interleukin 4 and interleukin 13). Taken together, this study clearly indicates that pre-treatment with 100 mg/kg of Pinus densiflora bark extract in gerbils can exert neuroprotection against brain ischemic injury by the attenuation of neuroinflammatory responses.

The initial effects of microclimate and invertebrate exclusion on multi-site variation in the mass loss of temperate pine and oak deadwoods

Quantifying deadwood decomposition is prioritized by forest ecologists; nonetheless, uncertainties remain for its regional variation. This study tracked variations in deadwood decomposition of Korean red pine and sawtooth oak in three environmentally different regions of the Republic of Korea, namely western, eastern, and southern regions. After 24 months, dead pine and oak woods lost 47.3 ± 2.8% and 23.5 ± 1.6% in the southern region, 13.3 ± 2.6% and 20.2 ± 2.8% in the western region, and 11.9 ± 7.9% and 13.9 ± 2.3% in the eastern region, respectively. The regional variation in the decomposition rate was significant only for dead pine woods (P < 0.05). Invertebrate exclusion treatment reduced the decomposition rate in all region, and had the greatest effect in the southern region where warmer climate and concentrated termite colonization occurred. The strongest influential factor for the decomposition of dead pine woods was invertebrate exclusion (path coefficient: 0.63). Contrastingly, the decomposition of dead oak woods was highly controlled by air temperature (path coefficient: 0.88), without significant effect of invertebrate exclusion. These findings reflect the divergence in regional variation of deadwood decomposition between pine and oak, which might result from the different sensitivity to microclimate and decomposer invertebrates.

Effectiveness of Sealer Combination Zinc Oxide (ZnO) with Red Pine (Pinus densiflora) on Viscosity and Solubility (Laboratory Experimental)

Background: Failure of endodontic treatment is caused by 60% of poor obturation. Sealers have an important role in the obturation process, that is filling the root canals and the space between the dentin and the core material. Sealers must have low viscosity so that they can flow easily and fill the entire root canal space so can form a good seal and have physical properties that are not easily soluble to oral fluids to prevent sealer degradation which can cause gaps during filling and become a medium for bacterial proliferation. Red pine extract is a natural ingredient that contain flavonoid and phenolic acid that are effective in reducing the viscosity and solubility of the sealer combination ZnO with red pine. Purpose: To determine the effectiveness of sealer combination ZnO with red pine in reducing viscosity and solubility. Methods: Red pine (Pinus densilora) extract with a concentration of 100% was diluted to a concentration of 0.78% using the dilution formula M1.VI = M2.V2. Viscosity test was done by mixing ZnO with red pine extract 0.78% 1: 1 and calcium hydroxide (Ca(OH)2) with 1: 1 sterile aquadest as a comparison, then each sample was measured for viscosity using a brookfield viscometer. The solubility test was carried out by placing the paste on a disc with a diameter of 15 mm x 3 mm and then being set and immersed in distilled water for 24 hours then the percentage of solubility was calculated. Results: The viscosity value of combination ZnO with red pine is 19.89 Pa.s and the solubility is 0.0075%, while Ca(OH)2 with sterile aquadest had a viscosity of 23.32 Pa.s and a solubility is 0.029%. Conclusion: The combination of ZnO with red pine is effective in reducing the viscosity and solubility of the combination sealer. The viscosity and solubility of the combined sealer is lower than Ca(OH)2 with sterile aquadest.

Human augmentation of historical red pine fire regimes in the Boundary Waters Canoe Area Wilderness

AbstractThe Border Lakes Region of Minnesota and Ontario has long been viewed as a fire‐dependent ecosystem. High‐severity fire in the region's near‐boreal forests has been a focus of ecological research and public fascination. However, the surface fire history within this transnational wilderness landscape has received more limited attention. We used an interdisciplinary, dendroecological approach to characterize the surface fire history of the region, assess potential drivers of historical surface fires, and document the ecological legacies of frequent fires within the red pine forests of the Boundary Waters Canoe Area Wilderness (BWCAW) in northern Minnesota. We used tree‐ring and fire atlas data to reconstruct multi‐century surface fire records for 101 sites and document age structure and composition at 32 sites across the BWCAW. Stratification of these sites relative to their proximity to a primary travel and trade corridor used first by Indigenous groups and later by Euro‐American fur traders through the late 1800s provided strong evidence of human augmentation of fires. The patterns of fire activity, fire–climate relationships, and forest development indicate that traditional landuse by Anishinaabeg (Ojibwe) increased rates of local surface fire and played an important role in shaping the landscape. The decline of traditional subsistence practices by the Border Lakes Anishinaabeg coincided with a sharp decline in surface fires and a period of abundant tree establishment. In the absence of repeat surface fires, many red pine sites have shifted in composition, increased in stem density, and grown vulnerable to forest‐type conversion through future high‐severity fire. These results highlight the need for active fire reintroduction to red pine forests of the Great Lakes Region and underscore the importance of collaboration and guidance from Indigenous Knowledge Keepers in this process. A blended knowledge approach to fire restoration that directly engages with Indigenous perspectives and cultural practices can perpetuate the distinctive character of the largest remaining tracts of long‐lived pine forest in the Great Lakes Region. Carefully developed fire restoration practices would enhance the visitor use experience within one of the most frequently visited wilderness areas in the United States while re‐engaging directly with Indigenous knowledge and traditional cultural practices.

Comparison of ratios combination calcium hydroxide Ca(OH)2 with red pine (Pinus densiflora) of viscosity

Background: Calcium hydroxide is a gold standard for root canal sealing material. However, there are many defects in calcium hydroxide that have prompted many researchers to look for alternative materials, including natural origin ingredients. Red pine (Pinus densiflora) is often used in dentistry for its antioxidant and antibacterial properties. The mixture of calcium hydroxide and red pine has never been achieved before. One of the criteria for material sealing is that the channel should be fully sealed with high flow ability and low viscosity. Therefore, this research is performed to analyze the viscosity value of the mixture of calcium hydroxide and red pine (Pinus densiflora). Purpose: Knowing the difference in viscosity of the combination of calcium hydroxide and red pine with a ratio of 1:1, 1:1.5, and 1:2. Methods: This study used four treatment groups, with each group consisting of 8 replications. Group 1 was a combination of calcium hydroxide and red pine with a 1: 1, group 2 the ratio was 1: 1.5, group 3 had the ratio 1: 2, and the positive control group used calcium hydroxide and a sterile aquadest. Calcium hydroxide in powder form and an extract of red pine in liquid form are mixed according to the ratio. The viscosity value is measured using a viscosity tester, namely the Brookfield Viscometer. Results: The control group had a lower viscosity than group 3, group 3, and group 2 than group1. Conclusion: Combination of calcium hydroxide and red pine with a ratio of 1:2, the lowest viscosity was obtained compared to the ratio of 1: 1 and 1: 1.5.

Amerika Birleşik Devletleri’nin güney eyaletlerinde yapılan ağaçlandırmaların Türkiye açısından değerlendirilmesi

Ağaçlandırmalar dünya ormanlık alanının %7’sini oluşturmasına karşın, toplam odun hammaddesi üretiminin %50’sini karşılamaktadır. Bu kapsamda, ABD’nin güney eyaletlerinde 1950’lerden bu yana çok başarılı ağaçlandırma çalışmaları yürütülmektedir. Bu çalışmalar için özel kuruluşlar, devlet orman işletmeleri ve üniversitenin bir araya geldiği bir kooperatif sistemi oluşturulmuştur. 1950’lerden bu yana ağaçlandırma alanları yaklaşık 15 kat, yıllık ortalama artım ise beş kat artırılmıştır. Ayrıca yıllık ortalama artımda sağlanan bu başarının bir sonucu olarak da idare süreleri 50 yıldan 18 yıla inmiştir. Türkiye’de de yarım yüzyılı aşkın bir süredir ağaçlandırma çalışmaları yürütülmektedir. Ayrıca ağaç ıslahında da Türkiye’de en büyük yayılış alanına sahip kızılçam için iyi bir alt yapı olduğu görülmektedir. Türkiye’deki ağaçlandırma çalışmalarının, devlet ve özel sektör tarafından geniş ölçüde benimsenmiş, ormancılık yönetiminin ayrılmaz bir parçası haline getirilmiş, sürdürülebilir bir yapı gösteremediği düşünülmektedir. Bu kapsamda ABD’nin güney eyaletlerinde yapılan ağaçlandırma çalışmaları incelenmiş ve Türkiye için bir değerlendirme yapılarak, öneriler getirilmiştir.

Preclinical Study on the Hepatoprotective Effect of Pollen Extract of Pinus brutia Ten. (Red Pine) in Mice and Phenolic Acid Analysis

Many agents, including those from herbal sources, have been sought as preventives or cures for hepatotoxicity. The pollen of Pinus brutia Ten., known as red pine (Pinaceae), is used against liver diseases in Anatolian folk medicine. In the current study, pollen ethanol extract of P. brutia was investigated for its possible hepatoprotective activity using a mouse model of CCl4-induced hepatotoxicity. Swiss albino mice were divided into five groups, and extract-treated groups were compared with a silymarin-treated group as the reference. The extract was tested at 100, 200, and 300 mg/kg (b.w.). Phenolic acids were analyzed using high-performance column chromatography (HPLC) in the extracts as pollens are usually known to be rich in phenolics. Our data revealed that the extract displayed the best hepatoprotection at a dose of 100 mg/kg when compared with silymarin (Legalon®), the reference drug. HPLC analysis indicated presence of protocatechuic acid (0.176 mg/g extract), p-hydroxybenzoic acid (0.001 mg/g extract), vanillic acid (VA) (0.537 mg/g extract), syringic acid (0.050 mg/g extract), and tr-cinnamic acid (0.310 mg/g extract), while the major phenolic acid was VA. The outcomes of this study allow us to conclude that red pine pollen extract can serve as a promising hepatoprotective agent. Among the phenolic acids analyzed in the pollen extract, vanillic acid as the major one besides some other phenolic acids detected seems to be responsible for its remarkable hepatoprotective effect.

Groundwater subsidizes tree growth and transpiration in sandy humid forests

AbstractAs drought variability increases in forests around the globe, it is critical to evaluate and understand ecosystem attributes that ameliorate drought impacts. Trees in arid and semi‐arid ecosystems can sustain tree growth and transpiration during drought by accessing shallow groundwater, yet the extent to which groundwater influences forest growth and transpiration in humid environments has largely been unexplored. We quantified groundwater's influence on tree growth and transpiration in northern humid forests with sandy soils. We hypothesized that even in wet regions, soil droughts occur relatively frequently in forests with sandy soils and result in water stress and reduced tree growth. Further, we hypothesized these reductions in productivity are ameliorated if the forest can access shallow groundwater during dry conditions. We evaluated tree growth responses using tree cores in Pinus resinosa trees and estimated forest groundwater use from diel water table fluctuations across sites covering a 1‐ to 9‐m depth‐to‐groundwater (DTG) gradient. In areas of shallow groundwater (DTG &lt; 2.5 m), we observed twice as much tree growth and high, frequent groundwater use (up to 81% of non‐rainy summer days). Groundwater's influence on tree growth and transpiration declined as groundwater deepened along the DTG gradient in the range 1–5 m below land surface. These findings suggest that water provided by a shallow water table subsidizes evapotranspiration in humid forests and results in enhanced tree growth. Our research provides a basis for understanding the role of groundwater in conferring drought resistance in humid forests to help guide sustainable water and forest management decisions.

Comparing long-term projected outcomes of adaptive silvicultural approaches aimed at climate change in red pine forests of northern Minnesota, USA

The Adaptive Silviculture for Climate Change (ASCC) project was developed to test ecosystem-specific adaptation approaches. The first ASCC trial was installed on the Cutfoot Experimental Forest (CEF) in northern Minnesota, USA, in 2014. Three adaptation treatments (resistance, resilience, and transition), along with a no action control, were tested and compared using Forest Vegetation Simulator to determine their relative success. We compared mean annual increment (MAI) and mortality and determined how well each treatment achieved its species composition and stand structure targets. MAI was highest in the no action (3.77 ± 0.43 m3·ha–1·year–1) and lowest in the transition (1.72 ± 0.16 m3·ha–1·year–1). However, MAI for the transition treatment continually increased over time, which extended culmination age. The no action control had the highest mortality with 38.76 (±1.32) trees·ha–1 per 10-year timestep, while the resistance and transition treatments had the lowest levels at 9.36 (±0.49) and 4.19 (±0.35) trees·ha–1, respectively. Our findings highlight the relative success of the transition, which had lower mortality, greater structural diversity, and a future-climate-adapted species composition. The results from this study provide important context for adaptive silviculture aimed at climate change and offers an example of potential outcomes of these forest adaptation options.

Classification of softwoods using wood extract information and near infrared spectroscopy

Three kinds of softwoods (Douglas fir, radiata pine, and Sugi) were used to test the possibility of their classification via near infrared (NIR) spectroscopy. In a previous study, the authors presented that the content of Korean softwood extractives (larix, red pine, Korean pine, cedar, and cypress) influenced wood classification. For expanding the extent of wood species to be considered in the analysis, three foreign wood species were newly introduced. Prior to comparing the NIR spectra obtained from the three softwoods, principal component analysis (PCA) was conducted to evaluate the possibility of discriminating the three foreign softwoods. The three species were also divided into three groups based on PCA, and a thin-layer chromatography (TLC) test improved the reliability of NIR-based wood classification via extractive contents. A similar pattern was obtained for alcohol-benzene eluted extractive compounds between same wood species.

Post-Fire Impacts of Vegetation Burning on Soil Properties and Water Repellency in a Pine Forest, South Korea

Forest fires can have a direct and immediate impact on soil properties, particularly soil water repellency. This study investigated the direct impacts of the Gangneung forest fire of 2019 on soil properties and the spatial variability of soil water repellency with vegetation burn severity in the Korean red pine (Pinus densiflora Siebold and Zucc) forest of South Korea. A total of 36 soil samples were collected at depth intervals of 0–5 cm, 10–15 cm, and 20–25 cm from three burned sites, representing surface-fuel consumption (SC), foliage necrosis (FN), and crown-fuel consumption (CC), respectively. An unburned site was also used as a control. Soil properties such as soil texture, pH, bulk density, electrical conductivity (EC), total organic carbon (TOC), and cation exchange capacity (CEC) were analyzed in the laboratory. The increase in the sand fraction near the soil surface after a fire was associated with changes in silt and clay fractions. Moderate to high vegetation burn severity at the FN and CC sites caused a decrease in soil pH due to the thermal destruction of kaolinite mineral structure, but organic matter combustion on the soil surface increased soil pH at the SC site. Forest fires led to increases in total organic carbon at the FN and SC sites, owing to the external input of heat damaged foliage and burnt materials. Molarity of an ethanol droplet (MED) tests were also conducted to measure the presence and intensity of soil water repellency from different locations and soil depths. MED tests showed that vegetation burn severity was important for determining the strength of water repellency, because severely burned sites tended to have stronger water repellency of soil than slightly burned sites. Unburned soils had very hydrophilic characteristics across soil depths, but a considerably thick hydrophobic layer was found in severely burned sites. The soil water repellency tended to be stronger on steep (&gt;30°) slopes than on gentle (&lt;15°) slopes.

Su Stresi Altındaki Bazı Kızılçam Kaynaklarının Tohum Çimlenme Oranı ve Fidelerin Gaz Değişim Performanslarının İncelenmesi

With climate change, global warming has increased adverse effects on living things in our country. In these adverse effects, water scarcity is the most crucial problem due to the increase in temperature and decrease in precipitation. Forests are the most affected ecosystem among others by water scarcity in our country. This study tried to determine the 5-year-old seeds and 1-year-old seedlings (produced from the same seeds) of some Turkish red pine provenance’ responses to different water stress levels. First, how the water stress levels (0, -0.2, -0.4, -0.6, -0.8 MPa) affect seed germination of these provenances was determined. Secondly, gas exchange parameters [net photosynthesis (Anet), stomatal conductance (gs), transpiration (E), and intrinsic water use efficiency (iWUE)] under different water stress were determined in the seedlings obtained from these species' seeds. As a result of the germination test, Denizli-Çameli (DC) provenance had the highest rate (48%), while Maraş-Suçatı had the lowest rate (29%) under control treatment. The highest germination rate was obtained in Burdur/Bucak provenance (5%) under -0.2 MPa osmotic potential. For gas exchange parameters, Antalya/Gündoğmuş provenance had the highest Anet, gs values while DC provenance had the lowest Anet, gs, and E values when provenance is considered as a single factor. Besides, increasing in irrigation increased Anet, gs, and E while decreased the iWUE. The lowest seedling E under water stress can be explained because this species responds to the water shortage by closing its stomata. Among the Turkish red pine origins, DC provenance showed higher drought tolerance than others.

Correction: Managing plantation density through initial spacing and commercial thinning: yield results from a 60-year-old red pine spacing trial experiment

Correction: Managing plantation density through initial spacing and commercial thinning: yield results from a 60-year-old red pine spacing trial experiment

Red pine (Pinus resinosa Ait.) fire history and management implications in the Mississippi River headwaters, Minnesota, USA

We used dendrochronological methods and remnant fire-scarred red pines (Pinus resinosa Ait.) to reconstruct historical fire regime characteristics and relate these findings to past climate, human land use changes, and vegetation for a landscape in northern Minnesota, USA. A total of 314 fire scars were dated, representing 56 unique fire events from 1565 to 1967. In the period prior to fire exclusion (1535–1935), fire intervals ranged from 1 to 40 years across the landscape and the mean fire interval was 6.6 years. The majority of fire scars (74%) occurred in the dormant season. Climate analyses showed that conditions two years before fire events were significantly wet and, in the year of fires, conditions were significantly dry. Overall, our study reveals complex interactions among climate, humans, and physiographic factors and how these have varied through time. For fire and forest management of red pine specifically, the results point to the use of silvicultural systems with high levels of retention, including non-stand replacing disturbances.

COMPUTATIONAL ANALYSIS OF PULVERIZED COAL CO-FIRING WITH BIOMASS IN 150MWe UNIT OF TUNCBILEK THERMAL POWER PLANT

Pulverized coal and biomass co-firing in the 150MWe unit of Tuncbilek power plant is computationally investigated, within the scope of a preliminary feasibility study. The considered furnace, burning Turkish lignite, has totally eighteen burners, positioned at three different levels. First, the pulverized coal combustion in the furnace is calculated and the predicted temperatures in the boiler first pass are compared with the previous measurements. Subsequently, a co-firing scenario is computationally analyzed, where the burners of the lowest level that supply 43% of the total fuel mass are fed by biomass, instead of coal. Turkish red pine is assumed to be the source of the biomass. In replacing the coal by biomass, the mass flow rates of the biomass and the corresponding air are adjusted in such a way that the thermal load and the equivalence ratio remain unaltered. Due to the lack of more accurate data for the biomass, the rate constants for the pyrolysis and chemical conversion of biomass are assumed to be the same as those of coal, along with the assumption of the same particle size distribution for both fuels. It is observed that the resulting flame structure for the case of co-firing is very similar to that of coal combustion. This result is encouraging for the application of biomass co-firing in the considered furnace.

Eastern Wood-Pewee (Contopus virens) reproductive success in red pine plantations and deciduous forests in Ontario, Canada

Pine plantations comprise about 7% of total world forest cover and are increasing across the globe. We compared settlement times, breeding densities, and the effects of time, habitat, and nest-site characteristics on the nest success of Eastern Wood-Pewees (Contopus virens) in red pine (Pinus resinosa) plantations and deciduous forest stands in south-central Ontario, Canada, in 2007 and 2008. Our goal was to evaluate the quality of these 2 habitats for this declining aerial insectivore. Pine plantations and deciduous forest stands were settled nearly simultaneously and at similar breeding densities, suggesting no preference for either habitat. Nest success in pine plantations (22%) was lower than in deciduous forests (35%), corresponding to higher counts of red squirrels (Tamiasciurus hudsonicus) and Blue Jays (Cyanocitta cristata) in plantations. Daily nest survival was lowest when nestlings were about 5 d old, but improved substantially as nestlings aged, and over the nesting season. In both habitats, increased nest visibility was correlated with decreased nest survival. In pine plantations, nest survival was higher where trees were more dispersed, while in deciduous forests, nests situated farther from tree trunks had higher survival rates. In both habitats, Eastern Wood-Pewees may use outward branches, when available, to detect movement and then evade potential nest predators. Although pine plantations provide breeding habitat for Eastern Wood-Pewees, management that increases hardwood understories and overstories may help to reduce visibility of Eastern Wood-Pewee nests and to reduce the populations of generalist songbird predators.

Radial variations in xylem sap flux in a temperate red pine plantation forest

BackgroundScaling sap flux measurements to whole-tree water use or stand-level transpiration is often done using measurements conducted at a single point in the sapwood of the tree and has the potential to cause significant errors. Previous studies have shown that much of this uncertainty is related to (i) measurement of sapwood area and (ii) variations in sap flow at different depths within the tree sapwood.ResultsThis study measured sap flux density at three depth intervals in the sapwood of 88-year-old red pine (Pinus resinosa) trees to more accurately estimate water-use at the tree- and stand-level in a plantation forest near Lake Erie in Southern Ontario, Canada. Results showed that most of the water transport (65%) occurred in the outermost sapwood, while only 26% and 9% of water was transported in the middle and innermost depths of sapwood, respectively.ConclusionsThese results suggest that failing to consider radial variations in sap flux density within trees can lead to an overestimation of transpiration by as much as 81%, which may cause large uncertainties in water budgets at the ecosystem and catchment scale. This study will help to improve our understanding of water use dynamics and reduce uncertainties in sap flow measurements in the temperate pine forest ecosystems in the Great Lakes region and help in protecting these forests in the face of climate change.