Red Pine Trees Research Articles

Historical fire regimes from red pines (Pinus resinosa Ait.) across the Tension Zone in the Lower Peninsula, Michigan USA

Currently, no multiple century fire scar records have been constructed in the Lower Peninsula of Michigan, USA, a region where historical vegetation ranged from prairies and oak-dominated woodlands in the south to conifer-northern hardwood forests and swamps to the north. The western portion of the Huron-Manistee National Forests is located within this strong vegetation transition (i.e., “Tension Zone”) and, based on this study, has well-preserved remnant red pine trees dating back to at least the late 1400s with fire scars dating back to 1523. From fire scar records constructed at four study sites, we documented historical fires as having a wide range of fire intervals and seasonalities. A general timeline of fire activity changes in this region can be described as relatively frequent fire in the pre- and early-European contact eras, variable and generally less fire from this point forward until the period of major logging activities after which fire frequency was significantly increased. Historical fires were associated with drought in the year of fire. Some broad synchronies of fire occurrence existed among sites such as 3 of 4 sites recording fires in years 1717, 1774, and 1829. Interestingly, these years were not exceptionally dry nor among the driest fire years. Future development of fire scar records will likely improve spatio-temporal characterization of regional fire regimes including understanding of human-climate-fire dynamics.

Temporal Transcriptome Profiling of Pinus densiflora Infected with Pine Wood Nematode Reveals Genetically Programmed Changes upon Pine Wilt Disease.

Pine, an evergreen conifer, is widely distributed worldwide. It is economically, scientifically, and ecologically important. However, pine wilt disease (PWD) induced by the pine wood nematode (PWN) adversely affects pine trees. Many studies have been conducted on the PWN and its beetle vectors to prevent the spread of PWD. However, studies providing a comprehensive understanding of the pine tree transcriptome in response to PWN infection are lacking. Here, we performed temporal profiling of the pine tree transcriptome using PWD-infected red pine trees, Pinus densiflora, inoculated with the PWN by RNA sequencing. Our analysis revealed that defense-responsive genes involved in cell wall modification, jasmonic acid signaling, and phenylpropanoid-related processes were significantly enriched 2 weeks after PWD infection. Furthermore, some WRKY-type and MYB-type transcription factors were upregulated 2 weeks after PWD infection, suggesting that these transcription factors might be responsible for the genome-wide reprogramming of defense-responsive genes in the early PWD stage. Our comprehensive transcriptome analysis will assist in developing PWD-resistant pine trees and identifying genes to diagnose PWD at the early stage of infection, during which large-scale phenotypic changes are absent in PWD-infected pine trees.

Morphological and molecular characterization of Paractinolaimus uljinensis n. sp. (Nematoda: Actinolaimidae) from Korea, with an updated compendium of the genus.

A new species of the genus Paractinolaimus isolated from the bark of a dead red pine tree was characterized using morphometric data and molecular DNA barcodes. Paractinolaimus uljinensis n. sp. was characterized by its medium sized body 2.50 to 2.98 mm long; lip region truncate, angular and offset by a depression; odontostyle 23.5 to 27.0 μm long; basal shield of pharynx present; vulval opening wide and longitudinal, positioned slightly anteriorly (V = 42.5-47.7); several advulval papillae; female tail long and filiform (324.0-435.0 μm long, c' = 10.1-14.2); a clearly visible copulatory hump; spicules 60.0 to 70.5 μm long; 12 to 15 (mostly 12-14) large contiguous ventromedian supplements, and male tail conoid to broadly rounded. The new species was morphologically compared with P. intermedius, P. sahandi, P. decraemerae, P. acutus, P. macrolaimus, and P. tuberculatus. The phylogenetic relationships among species were reconstructed using 18S- and 28S-rRNA gene sequences. The phylogenies showed well-supported sister relations of Paractinolaimus uljinensis n. sp. with P. sahandi, P. macrolaimus, and P. decraemerae. In addition, the ITS-rRNA gene sequences of Paractinolaimus uljinensis n. sp. were supplied, representing the first characterization of the gene for the genus.

Usability of fractometer for the purpose of a practical preliminary assessment tool for wood density of Pinus brutia

The fractometer is a device that breaks increment cores to measure fracture strength. The advantages of the device are that it is relatively fast, easy to use in the field, and it can perform direct strength measurements on increment cores. The main purpose of the study was to evaluate the usability of the fractometer as a preliminary evaluation tool for wood density traits of standing Turkish Pinus brutia (red pine) trees. Fracture strength was measured on 5 mm diameter increment cores, and X-ray densitometry was used for density measurements. Due to the high correlation between the two traits (fracture and density), a model was built using linear regression. Fifty trees were sampled to build the statistical model (r2: 0,74), and an equal sample size was used to test the model. The density value obtained from the model was 0,546 gcm-3, while the density value averaged by the X-ray method for the same group was 0,543 gcm-3. When considering mean values, it can be said that the model provides a good prediction. Based on personal experience and research results, some trees exhibited better growth and wood quality traits than others. Breeding from these trees could offer improvement in timber production and performance for Pinus brutia (red pine). As a general consequence, the fractometer and increment core sampling can be used for pine tree breeding programs for the preliminary assessment of wood density.

Innate Immune-Enhancing Effect of Pinus densiflora Pollen Extract via NF-κB Pathway Activation.

Considering the emergence of various infectious diseases, including the coronavirus disease 2019 (COVID-19), people's attention has shifted towards immune health. Consequently, immune-enhancing functional foods have been increasingly consumed. Hence, developing new immune-enhancing functional food products is needed. Pinus densiflora pollen can be collected from the male red pine tree, which is commonly found in Korea. P. densiflora pollen extract (PDE), obtained by water extraction, contained polyphenols (216.29 ± 0.22 mg GAE/100 g) and flavonoids (35.14 ± 0.04 mg CE/100 g). PDE significantly increased the production of nitric oxide (NO) and reactive oxygen species (ROS) but, did not exhibit cytotoxicity in RAW 264.7 cells. Western blot results indicated that PDE induced the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2. PDE also significantly increased the mRNA and protein levels of cytokines and the phosphorylation of IKKα/β and p65, as well as the activation and degradation of IκBα. Additionally, western blot analysis of cytosolic and nuclear fractions and immunofluorescence assay confirmed that the translocation of p65 to the nucleus after PDE treatment. These results confirmed that PDE increases the production of cytokines, NO, and ROS by activating NF-κB. Therefore, PDE is a promising nutraceutical candidate for immune-enhancing functional foods.

Using Acoustic Tomography to Infer Stem Wood Quality of Pine Forests Affected by a Fungal Pathogen in Different Latitudinal Regions and Plantation Densities

Diplodia pinea is a fungal pathogen that causes Diplodia shoot blight in pines and is widely spread in red pine (Pinus resinosa) and jack pine (Pinus banksiana) forests in Michigan. The objective of this study was to examine whether infection with D. pinea compromises wood quality in pine stands. Acoustic data was collected using an acoustic tomographer from the stem region at breast height (1.3 m) of red pine and jack pine trees across two categories of forest health condition (control vs. Diplodia-affected), in two latitudinal regions (Lower Peninsula vs. Upper Peninsula), and two levels of initial stand density (low vs. high). The acoustic data was used to infer the wood quality (i.e., density) in these two tree species since material of higher density generally has higher sound velocity rates. Red pine had significantly higher wood quality (i.e., higher sound velocities) in the Upper Peninsula region compared to the Lower Peninsula region. Within each latitudinal region, red pine sound velocities did not show significant differences between forest health condition or initial stand density levels. Jack pine showed no significant differences in sound velocities across the treatment categories. The results indicate that latitudinal region appears to have more impact on red pine wood quality than the influence of forest health condition (presence of Diplodia shoot blight) or initial stand density. All analyzed factors (latitudinal region, forest health condition, and stand density) did not have a significant impact on the wood quality of jack pine.

Modeling Climate Effects on Site Productivity of Plantation Grown Jack Pine, Black Spruce, Red Pine, and White Spruce Using Annual/Seasonal Climate Values

Site index (SI) is a commonly used measure of forest site productivity and is affected by climate change. Therefore, climate effects on site productivity were analyzed and modeled for jack pine (Pinus banksiana Lamb.), black spruce (Picea mariana (Mill.) B.S.P.), red pine (Pinus resinosa Ait.), and white spruce (Picea glauca (Moench) Voss) plantations using annual/seasonal values of climate variables. Jack pine and black spruce trees were each sampled from 25 plantations (sites), and red pine and white spruce trees were sampled from 30 and 31 plantations, respectively, from across Ontario, Canada. Stem analysis data collected from 201 jack pine, 211 black spruce, 90 red pine, and 93 white spruce trees were used in this study. To analyze and model climatic effects on site productivity, parameters of the stand height models were expressed in terms of climate variables. A nonlinear mixed-effects modelling approach was applied to fit the stand height models. Climate effects on site productivity was evaluated by predicting stand heights in three areas (the central, eastern/southeastern, and western parts of Ontario) for the period 2021 to 2080 under three emissions trajectories (representative concentration pathways (RCP) 2.6, 4.5, and 8.5 watts m−2). Climate effects on site productivity depended on tree species and location. For jack pine, climate effects were positive and pronounced only in western Ontario under all emissions scenarios. The effects were negative and mild after breast height age (BHA) 50 in central Ontario for black spruce. Similarly, the effects were negative and more pronounced at all areas after BHA 35 for red pine. On the other hand, for white spruce the effects were negative and highly pronounced from a young age under all scenarios, mainly in the southeast. For all species except for jack pine, climate effects were more pronounced under RCP 8.5 than the other two scenarios.

Pre-Columbian red pine (Pinus resinosa Ait.) fire regimes of north-central Pennsylvania, USA

BackgroundFire-dependent vegetation communities in the northeastern USA have undergone significant transitions since social and ecological disruptions associated with Euro-American colonization of North America. There is much interest, though little information available, about historical fire regimes of fire-adapted vegetation communities in the northeastern USA in pre-Columbian times (i.e., pre-1492 CE). We intensively investigated a red pine (Pinus resinosa Ait.)—oak (Quercus spp.) forested landscape in north-central Pennsylvania, USA, for exceptionally old red pine remnants (stumps, snags) where previous research had suggested the potential to develop fire-scar and tree-ring chronologies which extend to time periods prior to 1492.ResultsTree-ring and fire-scar chronologies recovered from red pine trees extend back to 1370 and 1402, respectively. Red pine trees were broadly distributed across this landscape (34.4 km2 area) prior to 1492, and frequent fire (i.e., mean fire return intervals of 4.1 years at landscape scale, 9.7–11.7 years at smaller spatial scales (0.5–7.1 km2)) was observed in the time period prior to sustained contact between Indigenous peoples and Euro-American colonizers circa 1609.ConclusionsThis study resulted in the longest fire-scar record in eastern North America and offers unique foundational ecological information regarding pre-Columbian fire regimes of northeastern USA fire-adapted forest communities. Fire scars provide physical evidence that fire was an important ecological component of this landscape before and after 1492 and that the current period of reduced fire activity is unprecedented in the 500 years prior to fire exclusion practices that were widely adopted circa 1915. Beyond fire scars, the spatial and temporal extent of the red pine tree-ring record provides evidence that red pine, a fire-dependent species, was historically a more important component of this landscape than it is today. The conservation of red pine vegetation communities will require incorporating recurring fire into management plans, for the successful regeneration and perpetuation of red pine, and to sustain associated flora and fauna of conservation concern.

Estimating tree Diameter at Breast Height (DBH) using an iPad Pro LiDAR sensor

ABSTRACT Diameter at Breast Height (DBH) plays an important role in forest management. New technologies such as airborne and terrestrial Light Detection and Ranging (LiDAR) are expensive and time-consuming. We explored the iPad LiDAR sensor to measure DBH considering affordability and availability. The study was carried out at a research forest plantation near Thunder Bay, Ontario, Canada. Five plots were selected for differences in stem spacing, average DBH and species, and made 360° scans separately. A manual circle fitting method was used to produce circular features for the estimation of DBH. The coefficient of determination (R 2) between estimated DBH and field measurements was 0.52, indicating a moderate accuracy. The Root Mean Square Error (RMSE) of DBH estimation ranged from 2.82 cm to 8.24 cm. The accuracy of smaller red pine trees was found to be relatively higher than that of larger red pine and white spruce trees. These accuracies did not change with the distance from the scanning location to trees. Therefore, results showed the potential use of an iPad LiDAR Scanner for DBH estimation. We recommend developing an application combining the iPad’s location and LiDAR sensors and incorporating a precise positioning method for fieldwork, and further broad field testing.

Density Functional Theory Calculations of Pinus brutia Derivatives and Its Response to Light in a Au/n-Si Device

In this study, the performance of an organic dye obtained from the bark of the red pine (Pinus brutia) tree growing in Muğla/Turkey as an interface layer in the Au/n-Si Schottky diode (SD) structure was evaluated. For this purpose, at first, the optimized molecular structure, the highest occupied molecular orbital (HOMO), and the lowest unoccupied molecular orbital (LUMO) simulations of the organic dye were calculated by the Gauss program and it was theoretically proven that the dye exhibits semiconducting properties. Then, the electrical and photodiode variables such as ideality factor, effective barrier height, series resistance, interface states density distribution, photosensitivity, and photo responsivity were evaluated employing current-voltage measurements under dark and different illumination densities. Additionally, C-V measurements were used to demonstrate that the fabricated device has capacitive features and this capability varies as a function of the frequency. Under these measurements, the possible conduction mechanism for the organic dye-based Au/n-Si device was investigated and the results showed that Au/Pinus brutia/n-Si may be a good candidate for optoelectronic applications.

Slate-red tarantula (Poecilotheria rufilata) in the Western Ghats, India

The Slate-red tree spider (or tarantula), Poecilotheria rufilata Pocock, 1899 is an extremely rare, endemic, little known tarantula described based on a female specimen from Thiruvananthapuram Kerala, India. This arboreal tree spider is mostly found in dead red pine, jack fruit, and white pine trees and recorded from Agasthyamala Biosphere Reserve, Peppara Dam, Kallar, and Ponmudi areas between 900–1200 m elevations in Kerala. It is morphologically similar to P. ornata Pocock, 1899, which is distributed in Sri Lanka.

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.

Evaluating red pine tree substrates for phytotoxicity and growth effects on seedlings and bedding plants

Evaluating red pine tree substrates for phytotoxicity and growth effects on seedlings and bedding plants

Modelling climate effects on diameter growth of red pine trees in boreal Ontario, Canada

The climate is changing and these changes may affect tree growth. Diameter growth models are one of the essential inputs for many growth and yield projection systems. Therefore, diameter growth models that can be used to estimate inside bark diameter at breast height (DBH) for red pine plantations in a changing climate were developed. One hundred and fifty red pine (Pinus resinosa Ait.) trees were sampled from 30 even-aged monospecific plantations (sites) (5 trees/site) across Ontario, Canada. Stem analysis data collected from these trees was used to develop and evaluate the growth models using a mixed effects modeling approach. Site and climate effects on diameter growth were examined by incorporating site and climate variables in the models. Including climate variables improved the fit statistics.Inside bark DBHs were predicted for 4 geographic areas of Ontario for the period 2021 to 2080. Three emissions trajectories known as representative concentration pathways (RCPs), each reflecting different levels of heat at the end of the century (i.e., 2.6, 4.5, and 8.5 W m−2), were evaluated. At the end of the 2021 to 2080 growth period, projected diameters were wider by 11% and 23% for trees in the southeastern and southwestern parts, respectively, and narrower by 6% for those in the central west part of Ontario (under all climate change scenarios relative to those under a no change scenario). However, no pronounced difference in projected diameters was evident for trees in the far west part of the province regardless of climate change scenario (relative to the no change scenario). In the absence of climate data, the model fitted without climate variables can be used to estimate inside bark DBH.

Multifaceted effects of chronic radiation exposure in Japanese red pines from Fukushima prefecture

Despite many studies carried out to date, the long-term effects of chronic exposure on plants and animals inhabiting the territories affected by the Fukushima Dai-Ichi NPP accident remain the subject of scientific discussions. Our investigations were performed on Japanese red pine, the native tree species that is widely spread in the radioactive contaminated areas. Earlier observations revealed the radiation-induced cancellation of the apical dominance in young trees of this species. To understand the mechanism of such transformation, we evaluated the morphometric parameters of needles, the frequency of cytogenetic abnormalities, and the concentrations of the major classes of phytohormones in several natural populations of young red pine trees growing under different exposure conditions in Fukushima prefecture. No significant relationships between the morphometric parameters of needles and dose rates at the experimental sites were revealed. The frequencies of aberrant cells in the needle's intercalary meristem and the frequencies of cancellation of the apical dominance in the young pine populations in the radioactive contaminated areas were significantly higher than in the reference population. However, only cytogenetic abnormalities increased with the dose rate. We have not found the relation between the frequency of cytogenetic abnormalities in needles and cancellation of the apical dominance in the individual trees. In this paper, for the first time, it is shown that chronic radiation exposure changes the concentration ratio of the major classes of phytohormones in the needles of Japanese red pine. Given the complete lack of information about the most important regulatory system of plants in chronically irradiated populations, this study fills a substantial gap in our knowledge. Finally, our findings indicated that the most probable causes of the cancellation of apical dominance observed in chronically exposed Japanese red pines are radiation damage to the apical meristems of the trees and changes in their phytohormonal balance.

Increasing Volumetric Prediction Accuracy—An Essential Prerequisite for End-Product Forecasting in Red Pine

Sustainable forest management requires accurate estimates of wood volume. At present, red pine (Pinus resinosa Sol. ex Aiton) is the most widely planted conifer tree species in southern Ontario, Canada. Therefore, inside and outside bark volume equations were developed for red pine trees grown in plantations. One hundred and fifty red pine trees were sampled from 30 even-aged plantations from across Ontario, Canada. Height-diameter pairs along the boles of sampled trees used to calculate stem volumes were obtained from stem analysis. Equations fitted to the data were a combined variable, modified combined variable, and modified form of dimensionally compatible volume equations. These equations were compared for their goodness-of-fit statistics, logical consistency, and predictive accuracy. The goodness-of-fit characteristics for all three equations were comparable for both inside and outside bark volumes. However, the estimated values for the intercept for the modified form of the dimensionally compatible and modified combined variable volume equations were negative and nonsignificant. The combined variable volume equation resulted in logically consistent parameter estimates in the presence of random effects parameters. Therefore, this equation was selected as the inside and outside bark volume equation for red pine trees grown in plantations. A nonlinear mixed-effects modeling approach was applied in fitting the final volume equation that included a weight (power function) to address heteroscedasticity. The equations developed here can be used to calculate inside and outside bark volumes of red pine plantations in boreal forests in Eastern Canada. These equations would require both diameter at breast height (DBH) and total height values in meters.

Incorporating stand density effects in modeling the taper of red pine plantations

Taper models are used to estimate the diameter at any height along the bole of a tree. Individual tree volume can then be calculated based on these diameters and corresponding heights. As tree diameters are affected by stand density, inside- and outside-bark taper models that incorporate stand density information were developed for trees in red pine (Pinus resinosa Aiton) plantations. Data used in this study came from stem analysis on 150 red pine trees sampled from 30 even-aged, monospecific plantations across Ontario, Canada. A nonlinear mixed-effects approach was applied in fitting these taper models. Several forms of stand density were evaluated for both inside- and outside-bark diameters. A combination of stand densities expressed as [Formula: see text] (BA, basal area; TPH, trees per hectare) explained the most variation in stem taper of trees grown in red pine plantations in Ontario. This variable was highly significant in the regression and improved the predictive accuracies of both inside- and outside-bark taper models. The taper models presented here are dimensionally compatible. Therefore, these models are applicable for data using any system of units without adjusting parameter values.

Using the Turkish Red Pine Tree to Monitor Heavy Metal Pollution

Using the Turkish Red Pine Tree to Monitor Heavy Metal Pollution

Quantifying the Effects of Wood Moisture and Temperature Variation on Time-of-Flight Acoustic Velocity Measures within Standing Red Pine and Jack Pine Trees

The relationship between the dynamic modulus of elasticity (me) of xylem tissue and acoustic velocity (vd) has been established for a number of commercially-important coniferous species, including red pine (Pinus resinosa Ait.) and jack pine (Pinus banksiana Lamb.). However, vd has been shown to vary systematically with xylem temperature (tx) and moisture (mx) for some species, and hence when the calibrated me–vd relationships are used outside of the range of conditions under which they were parameterized, erroneous predictions may arise. Consequently, the objectives of this study were (1) to investigate the significance of tx and mx effects on vd measurements within standing red pine and jack pine trees, and (2), given (1), to develop correction equations for standardizing vd measurements to referenced tx and mx conditions if warranted. Analytically, based on a temporal replicated sampling design, 26 mature red pine and 36 semi-mature jack pine trees growing in managed plantations located within central Ontario, Canada (Kirkwood Forest, Great Lakes—St. Lawrence Forest Region), were continuously measured for vd, tx, and mx during the spring-to-autumn seasonal periods in 2016 (red pine) and 2017 (jack pine). A total of 6 measurement events per species occurred at approximately 4–8 week intervals in which a total of 624 red pine and 864 jack pine cardinal-specific (north, east, south, and west) breast-height acoustic velocity, xylem temperature, and xylem moisture measurements were obtained: Yielding a total of 156 red pine and 216 jack pine mean tree-based values available for analysis. Over the sampling periods, (1) mean tree xylem temperatures ranged from a minimum of 3 °C to a maximum of 31 °C (mean = 19.2 °C) in red pine and from a minimum of 0 °C to a maximum of 27 °C (mean = 16.5 °C) in jack pine, and (2) mean tree xylem moistures ranged from a minimum 31% to a maximum of 45% (mean = 38.6%) in red pine and from a minimum 25% to a maximum of 50% (mean = 38.8%) in jack pine. Graphical examination of the moisture effect on the vd and tx relationship by tree and species revealed inversely proportional, linear-like trends at lower moisture levels and directly-proportional, linear-like trends at higher moisture levels where the effect was more evident for red pine than for jack pine. In order to describe this multivariate relationship, species-specific, two-level hierarchical, mixed-effects linear models inclusive of random and fixed effects were specified and subsequently parameterized. The first-level model described the tree-specific vd–tx relationship deploying a simple linear regression specification, whereas the second-level model expressed the first-level parameter estimates as a linear function of seasonal mean tree moisture. The resultant statistically-validated, parameterized regression models, for which 64% (red pine) and 90% (jack pine) of the vd variation was explained, indicated that the vd–tx relationship varied systematically with seasonal mean moisture level in red pine but not so in jack pine. More precisely, in red pine, vd declined with increasing tx at lower moisture levels (<38%), but increased with increasing tx at higher moisture levels (>38%). Conversely, although vd declined with increasing tx in jack pine, the relationship was unaffected by changes in seasonal mean tree moisture levels. Consequently, based on the final hierarchical model specifications, correction equations for adjusting observed vd values to standardized temperature (20 °C) and moisture conditions (40% for red pine) were developed for each species. Across the range of temperatures (≈5 °C–30 °C) and mean moisture levels (≈30–45%) examined, these equations generated a mean absolute vd adjustment of approximately 0.12 km/s for red pine and 0.04 km/s for jack pine. However, based on the corresponding relative magnitude of these adjustments which account for the narrow species-specific vd sample ranges observed (0.80 and 0.85 km/s for red pine and jack pine, respectively), the standardization of vd estimates could be of operational significance when acoustic sampling during periods in which xylem temperature and moisture levels approach the extremities of their spring-to-autumn seasonal ranges. Overall, the results of this empirical-based assessment, which confirmed the presence of temperature and moisture induced variation in acoustic velocity measures within standing red pine and jack pine trees, were largely in accordance with expectation. The subsequent provision of species-specific correction functions for adjusting observed vd sample values to corresponding equivalents referenced to standardized temperature and moisture conditions could assist in mitigating the consequences of environmental variability when acoustic sampling.

Climatic Effects on Site Productivity of Red Pine Plantations

Climatic effects on site productivity of red pine (Pinus resinosa Aiton) plantations were examined. A stand height/site index equation with climate variables incorporated in the height growth model was developed from stem analysis data. These data were collected from 90 dominant or co-dominant red pine trees sampled from even-aged monospecific plantations located on 30 sites (3 trees per site) broadly distributed across Ontario, Canada. The stand height equation was fit using a nonlinear mixed-effects approach. Climatic effects on site productivity were examined by regressing site index against commonly reported climate variables. Three site-specific climate attributes explained 63% of the variability in observed site index. These climate variables were examined to be incorporated into the stand height growth models. However, only two climate variables—growing season total precipitation (GSTP) and growing season mean temperature (GSMT)—were significant in the model without random effects and autocorrelation. In the presence of random effects and autocorrelation, however, only GSMT remained significant in the model. Stand heights were predicted for three randomly selected locations (eastern, western, and southern Ontario) for the growth periods 2011 to 2040 and 2041 to 2070 under two (2.6 and 8.5 Watts/m2) emissions trajectories known as Representative Concentration Pathways (RCPs). At the end of both growth periods, projected heights were reduced under both climate change scenarios (compared to those under a no-climate-change scenario) at all locations. Under both scenarios, the decrease in height growth was more pronounced in the south than in the east or west. The developed height growth models can be used to estimate stand heights for red pine plantations in a changing climate. Using the same models, site index of a plot/stand can also be estimated by calculating height at a given base (index) age. In the absence of climate data, the model fitted without climate variables can be applied to estimate stand heights and site indices.