Cajander Larch Research Articles

Linking Post-fire Tree Density to Carbon Storage in High-Latitude Cajander Larch (Larix cajanderi) Forests of Far Northeastern Siberia

AbstractWith climate warming and drying, fire activity is increasing in Cajander larch (Larix cajanderi Mayr.) forests underlain by continuous permafrost in northeastern Siberia, and initial post-fire tree demographic processes could unfold to determine long-term forest carbon (C) dynamics through impacts on tree density. Here, we evaluated above- and belowground C pools across 25 even-aged larch stands of varying tree densities that established following a wildfire in ~ 1940 near Cherskiy, Russia. Total C pools increased with increased larch tree density, from ~ 9,000 g C m−2 in low-density stands to ~ 11,000 g C m−2 in high and very high-density stands, with increases most pronounced at tree densities < 1 stem m−2 and driven by increased above- and belowground (that is, coarse roots) and live and dead (that is, woody debris and snags) larch biomass. Total understory vegetation and non-larch coarse root C pools declined with increased tree density due to decreased shrub C pools, but these pools were relatively small compared to larch biomass. Fine root, soil organic matter (OM), and near surface (0–30 cm) mineral soil (MS) C pools varied little with tree density, although soil C pools held most (18–28% in OM and 44–51% in MS) C stored in these stands. Thus, if changing fire regimes promote denser stands, C storage will likely increase, but whether this increase offsets C lost during fires remains unknown. Our findings highlight how post-fire tree demographic processes impact C pool distribution and stability in larch forests of Siberian permafrost regions.

Relationship between Dehydrins and Adaptation of Cajander Larch to Yakutia Cryolithozone Conditions

Composition and seasonal fluctuations of stress dehydrin proteins of Cajander larch (Larix cajanderi Mayr) growing under extremely cold climatic conditions in Central Yakutia, which are notable for an extraordinary frost resistance, were investigated. Immunoblotting technique made it possible to detect major dehydrins in a molecular mass range of 17–20, 37–42, and 73 kD in the shoots of L. cajanderi for the first time. A high level of polymorphism of dehydrins within a population of L. cajanderi was detected and differences between the examined specimens of trees were mainly revealed in a molecular mass range of 20–37 kD. Within the circannual cycle of larch, the greatest seasonal fluctuations were observed in low-molecular dehydrins, with their content rising at the end of phenological autumn and reaching a steady level in the period of ultralow winter temperatures. The pattern of seasonal fluctuations and wide variety of dehydrins in larch shoots may point to their possible participation in the formation of a unique frost resistance of L. cajanderi upon adaptation of this conifer species to conditions existing in the cryolithozone.

Allometric equations and wood density parameters for estimating aboveground and woody debris biomass in Cajander larch (Larix cajanderi) forests of northeast Siberia

Abstract. Boreal forests are particularly vulnerable to climate warming, which increases the occurrence of natural disturbances, such as fires and insect outbreaks. It is therefore essential to better understand climate-induced changes in boreal vegetation dynamics. This requires accurate estimates of variations in biomass across regions and time. This remains challenging in the extensive larch forests of northeast Siberia because of the paucity of allometric equations and physical properties of woody debris needed for quantifying aboveground biomass pools from field surveys. Our study is the first to present values of mean squared diameter (MSD) and specific gravity that can be used to calculate fine dead and downed woody debris loads in Cajander larch (Larix cajanderi) forests using the line-intersect sampling approach. These values were derived from field measurements collected in 25 forest stands in the Republic of Sakha, Russia, and compared with values reported for other prevalent boreal tree species. We developed allometric equations relating diameter at breast height (DBH, at 1.3 m) to stem wood, stem bark, branches, foliage, and aboveground biomass based on measurements of 63 trees retrieved from previous studies. Differences between our allometric models and existing equations were assessed in predicting larch aboveground biomass in 53 forest stands sampled in the Republic of Sakha. We found that using fine woody debris (FWD) parameters from other boreal tree species and allometric equations developed in other regions may result in significantly lower biomass estimates in larch-dominated forests of northeast Siberia. The FWD parameters and allometric equations presented in our paper can be used to refine estimates of aboveground biomass in Cajander larch forests in northeast Siberia.

Spatial patterns of unburned refugia in Siberian larch forests during the exceptional 2020 fire season

AbstractAimWildfire is an essential disturbance agent that creates burn mosaics, or a patchwork of burned and unburned areas across the landscape. Unburned patches, fire refugia, serve as carbon sinks and seed sources for forest regeneration in burned areas. In the Cajander larch (Larix cajanderi Mayr.) forests of north‐eastern Siberia, an unprecedented wildfire season in 2020 and little documentation of landscape patch dynamics have resulted in research gaps about the characteristics of fire refugia in northern latitude forests, which are warming faster than other global forest ecosystems. We aim to characterize the 2010 distribution of fire refugia for these forest ecosystems and evaluate their topographic drivers.LocationNorth‐eastern Siberia across the North‐east Siberian Taiga and the Cherskii‐Kolyma Mountain Tundra ecozones.Time period2001–2020.Major taxa studiedCajander larch.MethodsWe used Landsat imagery to define burned and unburned patches, and the Arctic digital elevation model to calculate topographic variables. We characterized the size and density of fire refugia. We sampled individual pixels (n = 80,000) from an image stack that included a binary burned/unburned, elevation, slope, aspect, topographic position index, ruggedness, and tree cover from 2001 to 2020. We evaluated the topographic drivers of fire refugia with boosted regression trees.ResultsWe found no substantial difference in fire refugia size and density across the region. The fire refugia size averaged 7.2 ha (0.09–150,439 ha). The majority of interior burned patches exceed the potential wind dispersal distance from fire refugia. Topographic position index and terrain steepness were important predictors of fire refugia.Main conclusionsUnprecedented wildfires in 2020 did not impact fire refugia formation. Fire refugia are strongly controlled by topographic positions such as uplands and lowlands that influence microsite hydrological conditions. Fire refugia contribute to postfire landscape heterogeneity that preserves ecosystem functions, seed sources, habitat, and carbon sinks.

Морфологическое разнообразие лиственницы Каяндера (Larix сajanderi Mayr) по форме семенных чешуй шишек в пенжинской популяции (Северная Корякия)

The diversity in the shape of cone scales of Larix cajanderi Mayr in the Penzhina population (North of Koryakia) was estimated using geometric morphometry methods. The study aimed in comparing the Penzhina population with other larch populations in Northeast Asia by the shape of cone scales and in identifying its geographical connections. A sample of 360 cones, collected from 36 larch trees in the middle reaches of the Penzhina River, was analyzed. Scales taken from the middle part of the cones were scanned, and outline points were placed with the screen digitizer using angular algorithm. Fourteen morphotypes of cone scales were distinguished by pairwise comparison of samples from each tree using Bootstrap resampling-based Goodall\'s F-test. These morphotypes were compared with those previously determined in the larch populations from Yakutia, Magadan Oblast, and the Kamchatka Peninsula. The morphotypes composition and frequency were used to determine phenotypic distances between populations. Cluster analysis and multidimensional scaling of the phenotypic distances were applied for ordination of the larch populations. All Penzhina morphotypes corresponded to the morphotypes of cone scales previously identified in the Yakutia and Magadan Cajander larch populations; two morphotypes were found earlier in the Kamchatka populations. By the shape of cone scales, the larch of the Penzhina population is close to the Yakutia populations of L. cajanderi. One can assume that the formation of larch forests in the Penzhina River valley mainly occurred due to the settlement of the larch from the Yakutia Pleistocene refugia. The Kamchatka cone scale morphotypes identical to those found in the Penzhina and Kolyma larch populations may indicate the migration of larch from the continent to the peninsula.

Recent above-ground biomass changes in central Chukotka (Russian Far East) using field sampling and Landsat satellite data

Abstract. Upscaling plant biomass distribution and dynamics is essential for estimating carbon stocks and carbon balance. In this respect, the Russian Far East is among the least investigated sub-Arctic regions despite its known vegetation sensitivity to ongoing warming. We representatively harvested above-ground biomass (AGB; separated by dominant taxa) at 40 sampling plots in central Chukotka. We used ordination to relate field-based taxa projective cover and Landsat-derived vegetation indices. A general additive model was used to link the ordination scores to AGB. We then mapped AGB for paired Landsat-derived time slices (i.e. 2000/2001/2002 and 2016/2017), in four study regions covering a wide vegetation gradient from closed-canopy larch forests to barren alpine tundra. We provide AGB estimates and changes in AGB that were previously lacking for central Chukotka at a high spatial resolution and a detailed description of taxonomical contributions. Generally, AGB in the study region ranges from 0 to 16 kg m−2, with Cajander larch providing the highest contribution. Comparison of changes in AGB within the investigated period shows that the greatest changes (up to 1.25 kg m−2 yr−1) occurred in the northern taiga and in areas where land cover changed to larch closed-canopy forest. As well as the notable changes, increases in AGB also occur within the land-cover classes. Our estimations indicate a general increase in total AGB throughout the investigated tundra–taiga and northern taiga, whereas the tundra showed no evidence of change in AGB.

Positive response of tree productivity to warming is reversed by increased tree density at the Arctic tundra–taiga ecotone

The transition zone between the northern boreal forest and the Arctic tundra, known as the tundra–taiga ecotone (TTE) has undergone rapid warming in recent decades. In response to this warming, tree density, growth, and stand productivity are expected to increase. Increases in tree density have the potential to negate the positive impacts of warming on tree growth through a reduction in the active layer and an increase in competitive interactions. We assessed the effects of tree density on tree growth and climate–growth responses of Cajander larch (Larix cajanderi Mayr.) and on trends in the normalized difference vegetation index (NDVI) in the TTE of Northeast Siberia. We examined 19 mature forest stands that all established after a fire in 1940 and ranged in tree density from 300 to 37 000 stems·ha−1. High-density stands with shallow active layers had lower tree growth, higher stand productivity, and more negative growth responses to growing season temperatures compared with low-density stands with deep active layers. Variation in stand productivity across the density gradient was not captured by Landsat-derived NDVI, but NDVI did capture annual variations in stand productivity. Our results suggest that the expected increases in tree density following fires at the TTE may effectively limit tree growth and that NDVI is unlikely to capture increasing productivity associated with changes in tree density.

Understory plant diversity and composition across a postfire tree density gradient in a Siberian Arctic boreal forest

Cajander larch (Larix cajanderi Mayr.) forests of the Siberian Arctic are experiencing increased wildfire activity in conjunction with climate warming. These shifts could affect postfire variation in the density and arrangement of trees and understory plant communities. To better understand how understory plant composition, abundance, and diversity vary with tree density, we surveyed understory plant communities and stand characteristics (e.g., canopy cover, active layer depth, and soil organic layer depth) within 25 stands representing a density gradient of similarly-aged larch trees that established following a 1940 fire near Cherskiy, Russia. Understory plant diversity and mean total plant abundance decreased with increased canopy cover. Canopy cover was also the most important variable affecting individual species’ abundances. In general, tall shrubs (e.g., Betula nana subsp. exilis) were more abundant in low-density stands with high light availability, and mosses (e.g., Sanionia spp.) were more abundant in high-density stands with low light availability. These results provide evidence that postfire variation in tree recruitment affects understory plant community composition and diversity as stands mature. Therefore, projected increases in wildfire activity in the Siberian Arctic could have cascading impacts on forest structure and composition in both overstory and understory plant communities.

Evaluating Post-Fire Vegetation Recovery in Cajander Larch Forests in Northeastern Siberia Using UAV Derived Vegetation Indices

The ability to monitor post-fire ecological responses and associated vegetation cover change is crucial to understanding how boreal forests respond to wildfire under changing climate conditions. Uncrewed aerial vehicles (UAVs) offer an affordable means of monitoring post-fire vegetation recovery for boreal ecosystems where field campaigns are spatially limited, and available satellite data are reduced by short growing seasons and frequent cloud cover. UAV data could be particularly useful across data-limited regions like the Cajander larch (Larix cajanderi Mayr.) forests of northeastern Siberia that are susceptible to amplified climate warming. Cajander larch forests require fire for regeneration but are also slow to accumulate biomass post-fire; thus, tall shrubs and other understory vegetation including grasses, mosses, and lichens dominate for several decades post-fire. Here we aim to evaluate the ability of two vegetation indices, one based on the visible spectrum (GCC; Green Chromatic Coordinate) and one using multispectral data (NDVI; Normalized Difference Vegetation Index), to predict field-based vegetation measures collected across post-fire landscapes of high-latitude Cajander larch forests. GCC and NDVI showed stronger linkages with each other at coarser spatial resolutions e.g., pixel aggregated means with 3-m, 5-m and 10-m radii compared to finer resolutions (e.g., 1-m or less). NDVI was a stronger predictor of aboveground carbon biomass and tree basal area than GCC. NDVI showed a stronger decline with increasing distance from the unburned edge into the burned forest. Our results show NDVI tended to be a stronger predictor of some field-based measures and while GCC showed similar relationships with the data, it was generally a weaker predictor of field-based measures for this region. Our findings show distinguishable edge effects and differentiation between burned and unburned forests several decades post-fire, which corresponds to the relatively slow accumulation of biomass for this ecosystem post-fire. These findings show the utility of UAV data for NDVI in this region as a tool for quantifying and monitoring the post-fire vegetation dynamics in Cajander larch forests.

Impacts of increased soil burn severity on larch forest regeneration on permafrost soils of far northeastern Siberia

Fire severity is increasing across the boreal forest biome as climate warms, and initial post-fire changes in tree demographic processes could be important determinants of long-term forest structure and carbon dynamics. To examine soil burn severity impacts on tree regeneration, we conducted experimental burns in summer 2012 that created a gradient of residual post-fire soil organic layer (SOL) depth within a mature, sparse-canopy Cajander larch (Larix cajanderi Mayr.) forest in the Eastern Siberian Arctic. Each fall from 2012 to 2016, we added larch seeds to plots along the burn severity gradient. We tracked density of new larch germinants and established seedlings (alive ≥ 1 year) during subsequent growing seasons, along with changes in seedbed conditions (permafrost thaw depth, moisture, and temperature). Over the study, a cumulative total of 17 and 18 new germinants m−2 occurred in high and moderate severity treatments, respectively, while germinants were rare in unburned and low severity treatments (< 0.5 germinants m−2). Most seedlings (> 50%) germinated in summer 2017, following a mast event in fall 2016, suggesting safe sites for germination were not fully occupied in previous years despite seed additions. By 2017, established seedling density was ∼5 times higher on moderate and high severity treatments compared to other treatments. Cumulative total density of new germinants and established seedlings increased linearly with decreasing residual SOL depth, as did thaw depth, soil moisture, and soil temperature. Our findings suggest that increased soil burn severity could improve seedbed conditions and increase larch recruitment, assuming seed sources are available. If these demographic changes persist as stands mature, a climate-driven increase in soil burn severity could shift forest structure from sparse-canopy stands, which dominate this region of the Siberian Arctic, to high density stands, with potential implications for carbon, energy, and water cycling.

Investigation of the main practically important extractive substances of the Larix cajanderi Mayr. Heartwood

The extractive substances of the wood of Cajander larch (Larix cajanderi Mayr.) growing in the areas of Magadan oblast under various climatic conditions have been investigated. It has been found that the investigated wood contains up to 4.5% of flavonoids and up to 15.5% of water-soluble polysaccharide arabinogalactan that defines the perspective of its application for the industrial production of these valuable biologically active substances.

Plant response to climate change along the forest‐tundra ecotone in northeastern Siberia

Russia's boreal (taiga) biome will likely contract sharply and shift northward in response to 21st century climatic change, yet few studies have examined plant response to climatic variability along the northern margin. We quantified climate dynamics, trends in plant growth, and growth-climate relationships across the tundra shrublands and Cajander larch (Larix cajanderi Mayr.) woodlands of the Kolyma river basin (657000km(2) ) in northeastern Siberia using satellite-derived normalized difference vegetation indices (NDVI), tree ring-width measurements, and climate data. Mean summer temperatures (Ts ) increased 1.0°C from 1938 to 2009, though there was no trend (P>0.05) in growing year precipitation or climate moisture index (CMIgy ). Mean summer NDVI (NDVIs ) increased significantly from 1982 to 2010 across 20% of the watershed, primarily in cold, shrub-dominated areas. NDVIs positively correlated (P<0.05) with Ts across 56% of the watershed (r=0.52±0.09, mean±SD), principally in cold areas, and with CMIgy across 9% of the watershed (r=0.45±0.06), largely in warm areas. Larch ring-width measurements from nine sites revealed that year-to-year (i.e., high-frequency) variation in growth positively correlated (P<0.05) with June temperature (r=0.40) and prior summer CMI (r=0.40) from 1938 to 2007. An unexplained multi-decadal (i.e., low-frequency) decline in annual basal area increment (BAI) occurred following the mid-20th century, but over the NDVI record there was no trend in mean BAI (P>0.05), which significantly correlated with NDVIs (r=0.44, P<0.05, 1982-2007). Both satellite and tree-ring analyses indicated that plant growth was constrained by both low temperatures and limited moisture availability and, furthermore, that warming enhanced growth. Impacts of future climatic change on forests near treeline in Arctic Russia will likely be influenced by shifts in both temperature and moisture, which implies that projections of future forest distribution and productivity in this area should take into account the interactions of energy and moisture limitations.

Генетическое разнообразие, популяционная структура и дифференциация лиственниц сибирской, Гмелина и Каяндера по данным SSR-маркеров

The genetic diversity of SSR markers was studied in six populations of Siberian larch, two populations of Gmelin larch, and four populations of Cajander larch. Seven pairs of nuclear microsatellite loci were used for this analysis. 103 allelic variants were detected in 365 individuals of three species of larch. According to the AMOVA results, the variability proportion that characterizes the differences between three Larix species was twice as higher (15%) than the proportion that accounts for among-population differences within the species (6%). The differentiation of the populations of three species of larch based on SSR markers exceeded 12% (FsT = 0.121). A significant correlation of the genetic distances with the geographic distances between populations was found (r = 0.835, P = 0.01).

Corrigendum to &amp;quot;Cajander larch (&amp;lt;i&amp;gt;Larix cajanderi&amp;lt;/i&amp;gt;) biomass distribution, fire regime and post-fire recovery in northeastern Siberia&amp;quot; published in Biogeosciences, 9, 3943−3959, 2012

Corrigendum to “Cajander larch (Larix cajanderi) biomass distribution, fire regime and post-fire recovery in northeastern Siberia” published in Biogeosciences, 9, 3943–3959, 2012 L. T. Berner1, P. S. A. Beck1, M. M. Loranty1,*, H. D. Alexander2,**, M. C. Mack2, and S. J. Goetz1 1The Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA 02540-1644, USA 2University of Florida, Department of Biology, P.O. Box 118525, Gainesville, FL 32611, USA *currently at: Colgate University, Department of Geography, 13 Oak Drive, Hamilton, NY 13346, USA **currently at: University of Texas – Brownsville, Department of Biological Sciences, 80 Fort Brown, Brownsville, TX 78520, USA Correspondence to: L. T. Berner (lberner@whrc.org)

Effect of site conditions on the formation of wood anatomical structure in the cajander larch (Larix cajanderi Mayr) in the Amur region

Studies on the Cajander larch (Larix cajanderi) in the Amur region have been performed to evaluate the effect of growth conditions on the development of wood anatomical structure during ontogeny, including the course and rate of definitive (mature) wood formation. Adaptive changes in wood anatomy have been revealed in trees growing in waterlogged areas underlain by permafrost.

Cajander larch (&amp;lt;i&amp;gt;Larix cajanderi&amp;lt;/i&amp;gt;) biomass distribution, fire regime and post-fire recovery in northeastern Siberia

Abstract. Climate change and land-use activities are increasing fire activity across much of the Siberian boreal forest, yet the climate feedbacks from forest disturbances remain difficult to quantify due to limited information on forest biomass distribution, disturbance regimes and post-disturbance ecosystem recovery. Our primary objective here was to analyse post-fire accumulation of Cajander larch (Larix cajanderi Mayr.) aboveground biomass for a 100 000 km2 area of open forest in far northeastern Siberia. In addition to examining effects of fire size and topography on post-fire larch aboveground biomass, we assessed regional fire rotation and density, as well as performance of burned area maps generated from MODIS satellite imagery. Using Landsat imagery, we mapped 116 fire scar perimeters that dated c. 1966–2007. We then mapped larch aboveground biomass by linking field biomass measurements to tree shadows mapped synergistically from WorldView-1 and Landsat 5 satellite imagery. Larch aboveground biomass tended to be low during early succession (≤ 25 yr, 271 ± 26 g m−2, n = 66 [mean ± SE]) and decreased with increasing elevation and northwardly aspect. Larch aboveground biomass tended to be higher during mid-succession (33–38 yr, 746 ± 100 g m−2, n = 32), though was highly variable. The high variability was not associated with topography and potentially reflected differences in post-fire density of tree regrowth. Neither fire size nor latitude were significant predictors of post-fire larch aboveground biomass. Fire activity was considerably higher in the Kolyma Mountains (fire rotation = 110 yr, fire density = 1.0 ± 1.0 fires yr−1 × 104 km−2) than along the forest-tundra border (fire rotation = 792 yr, fire density = 0.3 ± 0.3 fires yr−1 × 104 km−2). The MODIS burned area maps underestimated the total area burned in this region from 2000–2007 by 40%. Tree shadows mapped jointly using high and medium resolution satellite imagery were strongly associated (r2 &amp;amp;approx; 0.9) with field measurements of forest structure, which permitted spatial extrapolation of aboveground biomass to a regional extent. Better understanding of forest biomass distribution, disturbances and post-disturbance recovery is needed to improve predictions of the net climatic feedbacks associated with landscape-scale forest disturbances in northern Eurasia.

Carbon Accumulation Patterns During Post-Fire Succession in Cajander Larch (Larix cajanderi) Forests of Siberia

Increased fire activity within boreal forests could affect global terrestrial carbon (C) stocks by decreasing stand age or altering tree recruitment, leading to patterns of forest regrowth that differ from those of pre-fire stands. To improve our understanding of post-fire C accumulation patterns within boreal forests, we evaluated above- and belowground C pools within 17 Cajander larch (Larix cajanderi) stands of northeastern Siberia that varied in both years since fire and stand density. Early-successional stands ( 70-year old), aboveground larch biomass, ANPPtree, and soil organic layer C pools increased with stand age. These stands were low density and multi-aged, containing both mature trees and new recruits. The rapid accumulation of aboveground larch biomass in high-density, mid-successional stands allowed them to obtain C stocks similar to those in much older low-density stands (~8,000 g C m−2). If fire frequency increases without altering stand density, landscape-level C storage could decline, but if larch density also increases, large aboveground C pools within high-density stands could compensate for a shorter successional cycle.

Botanical-geographical and forestry aspects of introgressive hybridization of the Gmelin’s larch (Larix gmelinii (Rupr.) Rupr.) and Cajander larch (L. cajanderi Mayr)

The paper studies the introgressive hybridization between the Gmelin’s larch and Cajander larch. The obtained data confirm the indisputable specific independence of the Cajander larch, which occupies about 48% of the total area of the larch forests in Russia. Its specific independence has been doubted by some experts. Once again more reliable and vast material shows the presence of wide transitional belt of hybrid populations at the juncture of the hybridizing species. Some forestry characteristics of the Gmelin’s larch and Cajanderi larch are studied that play important role in their natural restoration.

Characteristics of Cajander Larch (Larix cajanderi Mayr) on Dredging Waste Dumps in the Amur Region

Former dredging sites were studied in the taiga zone of the Amur region (in Khabarovsk Krai). The involvement of Larix cajanderi in plant succession on dredging waste dumps was revealed. Some morphological-anatomical parameters of L. cajanderi needles were compared in trees growing on the dumps and in adjacent open larch stands on waterlogged peaty soils.