scholarly journals Growth characteristics of natural and planted Dahurian larch in northeast China

2017 ◽  
Author(s):  
Bingrui Jia ◽  
Guangsheng Zhou

Abstract. Dahurian larch (Larix gmelinii Rupr.) is the dominant species in both natural and planted forests in northeast China, which situated in the southernmost part of the global boreal forest biome and undergoing the greatest climatically induced changes. Published studies (1965–2015) on tree aboveground growth of Larix gmelinii forests in northeast China were collected in this study, critically reviewed, and a comprehensive growth dataset was developed from 123 sites, which distributed between 40.85° N and 53.47° N in latitude, between 118.20° E and 133.70° E in longitude, between 130 m and 1260 m in altitude. The dataset was composed of 776 entries, including growth data (mean tree height, mean DBH, mean tree volume and/or stand volume) and the associated information, i.e., geographical location (latitude, longitude, altitude, aspect and slope), climate (mean annual temperature (MAT) and mean annual precipitation (MAP)), stand description (origin, stand age, stand density and canopy density), and sample regime (observing year, plot area and number). It would provide quantitative references for plantation management practices and boreal forest growth prediction under future climate change. The DOI for the data is https://doi.org/10.1594/PANGAEA.880984.

2018 ◽  
Vol 10 (2) ◽  
pp. 893-898
Author(s):  
Bingrui Jia ◽  
Guangsheng Zhou

Abstract. Dahurian larch (Larix gmelinii Rupr.) is the dominant species in both natural and planted forests in northeast China, which is situated in the southernmost part of the global boreal forest biome and is undergoing great climatically induced changes. Published studies (1965–2015) on tree above-ground growth of Dahurian larch forests in northeast China were collected in this study and critically reviewed, and a comprehensive growth data set was developed from 122 sites, which are distributed between 40.85 and 53.47∘ N in latitude, between 118.20 and 133.70∘ E in longitude and between 130 and 1260 m in altitude. The data set is composed of 743 entries and includes growth data (mean tree height, mean diameter at breast height (DBH), mean tree volume and/or stand volume) and associated information, i.e., geographical location (latitude, longitude, altitude, aspect and slope), climate (mean annual temperature (MAT) and mean annual precipitation (MAP)), stand description (origin, stand age, stand density and canopy density) and sample regime (observation year, plot area and plot number). It provides a quantitative reference for plantation management practices and boreal forest growth prediction under future climate change. The data set is freely available for noncommercial scientific applications, and the DOI for the data is https://doi.org/10.1594/PANGAEA.880984.


2007 ◽  
Vol 49 (1) ◽  
pp. 81-98 ◽  
Author(s):  
Robert E. Vance ◽  
Alwynne B. Beaudoin ◽  
Brian H. Luckman

ABSTRACTSynthesis of available paleoecological studies in the Prairie provinces of Canada indicates that although the peak in postglacial aridity that characterized early Holocene climate of the western foothills and plains had passed, conditions remained warmer and drier than present throughout the region ca. 6000 yr BP Compared to today, treeline elevations were higher and alpine glaciers were reduced in size in the Rocky Mountains, lake levels were lower over much of the Interior Plains, and the grassland and boreal forest ecozones extended north of their present positions. Forest fires were more prevalent ca. 6000 yr BP than they are today, aiding westward migration of jack pine (Pinus banksiana) through the boreal forest and increasing the area occupied by grassland in boreal and montane forest regions. Attempts to quantify the magnitude of 6 ka temperature and precipitation differences have produced variable results, but suggest that mean annual temperature was 0.50°C to 1.50°C higher than today (summer temperature may have been up to 3°C higher) and mean annual precipitation was reduced by 65 mm (or summer precipitation was reduced by 50 mm), compared to present. The nature and scale of these changes suggests that a vigorous zonal atmospheric circulation pattern, similar to that of the 1930s but shifted northward, prevailed at 6 ka.


Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1302
Author(s):  
Yanli Xu ◽  
Lichun Jiang ◽  
Muhammad Khurram Shahzad

Stem taper function is an important concept in forest growth and yield modeling, and forest management. However, the additivity of the function and the inherent correlations between stem components (diameter outside bark—dob, diameter inside bark—dib, and double-bark thickness—dbt) are seldom considered. In this paper, a total disaggregation model (TDM) structure was developed based on the well-known Kozak (2004) model to ensure the additivity of the stem components. The reconstructed model was fitted with the data of 1281 felled Dahurian larch trees from three regions of Daxing’anling Mountains in Northeast China. The results from TDM were compared with other additive model structures including adjustment in proportion (AP), non-additive taper models (NAM), and three logical structures of NSUR (AMO, SMI, SMB). The results showed that the difference was significant among the three regions. The performance of TDM was slightly better than those of other model structures. Therefore, TDM was considered as another optimal additive system to estimate stem, bark thickness, and volume predicting for Dahurian larch in Northeast China besides NSUR, a method widely used in calculating additive volume or biomass throughout the world. We believe this work is cutting-edge, and that this methodology can be applied to other tree species.


2021 ◽  
Author(s):  
Marie Spohn ◽  
Johan Stendahl

Abstract. While the carbon (C) content of temperate and boreal forest soils is relatively well studied, much less is known about the ratios of C, nitrogen (N), and phosphorus (P) of the soil organic matter, and the abiotic and biotic factors that shape them. Therefore, the aim of this study was to explore carbon, nitrogen, and organic phosphorus (OP) contents and element ratios in temperate and boreal forest soils and their relationships with climate, dominant tree species, and soil texture. For this purpose, we studied 309 forest soils with a stand age >60 years located all over Sweden between 56° N and 68° N. The soils are a representative subsample of Swedish forest soils with a stand age >60 years that were sampled for the Swedish Forest Soil Inventory. We found that the N stock of the organic layer increased by a factor of 7.5 from −2 °C to 7.5 °C mean annual temperature (MAT), it increased almost twice as much as the organic layer stock along the MAT gradient. The increase in the N stock went along with an increase in the N : P ratio of the organic layer by a factor of 2.1 from −2 °C to 7.5 °C MAT (R2 = 0.36, p < 0.001). Forests dominated by pine had higher C : N ratios in the litter layer and mineral soil down to a depth of 65 cm than forests dominated by other tree species. Further, also the C : P ratio was increased in the pine-dominated forests compared to forests dominated by other tree species in the organic layer, but the C : OP ratio in the mineral soil was not elevated in pine forests. C, N and OP contents in the mineral soil were higher in fine-textured soils than in coarse-textured soils by a factor of 2.3, 3.5, and 4.6, respectively. Thus, the effect of texture was stronger on OP than on N and C, likely because OP adsorbs very rigidly to mineral surfaces. Further, we found, that the P and K concentrations of the organic layer were inversely related with the organic layer stock. The C and N concentrations of the mineral soil were best predicted by the combination of MAT, texture, and tree species, whereas the OP concentration was best predicted by the combination of MAT, texture and the P concentration of the parent material in the mineral soil. In the organic layer, the P concentration was best predicted by the organic layer stock. Taken together, the results show that the N : P ratio of the organic layer was most strongly related to MAT. Further, the C : N ratio was most strongly related to dominant tree species, even in the mineral subsoil. In contrast, the C : P ratio was only affected by dominant tree species in the organic layer, but the C : OP ratio in the mineral soil was hardly affected by tree species due to the strong effect of soil texture on the OP concentration.


Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 454
Author(s):  
Bin Wang ◽  
Mingze Li ◽  
Wenyi Fan ◽  
Ying Yu ◽  
Weiwei Jia

Although CO2 fertilization on plant growth has been repeatedly modeled to be the main reason for the current changes in the terrestrial carbon sink at the global scale, there have been controversial findings on the CO2 fertilization effects on forests from tree-ring analyses. In this study, we employed conventional dendrochronological tree-ring datasets from Northeast China, to detect the effect of CO2 fertilization on Larix gmelinii growth from 1950 to 2010. Among four sites, there were two sites exhibiting a significant residual growth enhancement at a 90% confidence level after removing the size, age and climaterelated trends of tree-ring indices. In addition, we found consistency (R from 0.26 to 0.33, p < 0.1) between the high frequency CO2 fluctuation and residual growth indices at two of the four sites during the common period. A biogeochemical model was used to quantitatively predict the contribution of elevated atmospheric CO2 on accumulated residual growth enhancement. As found in the tree-ring data, 14% of the residual growth was attributed to the CO2 fertilization effect, while climate was responsible for approximately the remainding 86%.


Author(s):  
Cong He ◽  
Jia-Rui Niu ◽  
Cheng-Tang Xu ◽  
Shou-Wei Han ◽  
Wei Bai ◽  
...  

Northeast China(NEC) is the main grain-producing area in China, but soil degradation is severe due to the long-term use of conventional tillage(CT). It is necessary to restore soil fertility, maintain crop yield, and enhance sustainability using conservation tillage in NEC. However, the integrated effects of conservation tillage on crop yield and SOC under different conditions in NEC are still unclear. Using 70 peer-reviewed papers, we assessed the crop yield and SOC sequestration effect, and their relationship under no-till(NT), ridge tillage(RT), and subsoiling tillage(ST) in NEC. The results indicated that in areas with a mean annual temperature (MAT) < 3℃, yield under NT was significantly lower than CT by 3.7% whereas RT and ST were higher than CT by 0.8% and 13.1% (P<0.05). RT generally had a similar effect on yield as NT, but RT did not have a negative impact on yield in colder regions, indicating that this may be a more suitable conservation tillage practice in these areas. ST may be used in rotation with other tillage measures to maintain crop yield if necessary. NT could increase SOC concentration by 24.1%, 43.9%, and 17.4% under high MAT (>6℃), low mean annual precipitation (MAP) (<500mm), and continuous cropping, respectively. The mean SOC sequestration rate under NT, RT, and ST was 0.953, 0.099, and 0.101 Mg C ha-1 yr-1, respectively. Overall, the implementation of different conservation tillage measures in NEC can enhance crop yield as well as carbon sequestration, indicating its potential to be popularized in NEC.


2019 ◽  
Vol 99 (4) ◽  
pp. 955-961 ◽  
Author(s):  
Tan Bao ◽  
Cameron N. Carlyle ◽  
Edward W. Bork ◽  
Marcus Becker ◽  
Mike J. Alexander ◽  
...  

A survey of Alberta beef producers was conducted at sites overlapping with a province-wide network of permanent biodiversity monitoring plots to characterize focal pastures and their management, including estimates of stocking rates. Overall, greater stocking rates were reported in the boreal compared with the parkland and grassland natural regions, coinciding with an increased reliance on tame forage on relatively small land areas of largely deeded land. Higher stocking rates were also associated with earlier starting dates of grazing in the season, higher mean annual precipitation, and lower mean annual temperature.


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