Interpreting Larix principis-rupprechtii radial growth in northern China based on the Vaganov-Shashkin model

Changes in annual radial growth is an important indication of climate change. Dendroclimatology studies in northern China have focused on linear statistical analysis,but lacking studies based on the process of ring formation to clarify the radial growth of trees. Tree-ring width standard chronology(STD) was established using samples of Larix principis-rupprechtii collected at 2303 m altitude on Luya Mountain. Using the Vaganov-Shashkin(VS) model to simulate growth and development, the internal physiological mechanism of radial growth is identified. It was concluded that:(1) the growing season of L. principis-rupprechtii was May to September;(2) soil moisture was a significant factor in the early and late growing seasons, and temperature was the dominant factor in its main growth period;and(3) formation of narrow ring widths was closely related to drought stress, the development of wide ring widths will be restricted by increasing future temperatures. The VS model is applicable for radial growth simulation of subalpine coniferous forests and for guiding the cultivation of local tree species in the future.

Effects of rainfall patterns on annual plants in Horqin Sandy Land, Inner Mongolia of China

Growth of annual plants in arid environments depends largely on rainfall pulses. An increased understanding of the effects of different rainfall patterns on plant growth is critical to predicting the potential responses of plants to the changes in rainfall regimes, such as rainfall intensity and duration, and length of dry intervals. In this study, we investigated the effects of different rainfall patterns（e.g. small rainfall event with high frequency and large rainfall event with low frequency） on biomass, growth characteristics and vertical distribution of root biomass of annual plants in Horqin Sandy Land, Inner Mongolia of China during the growing season（from May to August） of 2014. Our results showed that the rainfall patterns, independent of total rainfall amount, exerted strong effects on biomass, characteristics of plant growth and vertical distribution of root biomass. Under a constant amount of total rainfall, the aboveground biomass（AGB）, belowground biomass（BGB）, plant cover, plant height, and plant individual and species number increased with an increase in rainfall intensity. Changes in rainfall patterns also altered the percentage contribution of species biomass to the total AGB, and the percentage of BGB at different soil layers to the total BGB. Consequently, our results indicated that increased rainfall intensity in future may increase biomass significantly, and also affect the growth characteristics of annual plants.

Dynamics of annual growth of Pinus sylvestris on industrial wastes of mining companies

The development of the mining industry has led to the appearance in many parts of the world of vast technogenic territories from which toxic heavy metals enter the environment and food chains.Physical,chemical,and biological methods of cleaning industrial land due to technological complexity and hi gh cost are relatively little used on a large scale.Natural forest overgrowth of mining sites and the removal of heavy metals by woody plants can be an effective form of recovery.Therefore,the study of this process is of significant scientific and practical interest.The analysis of the annual growth in height and width of the annual rings of the stem of Scots pine(Pinus sylvestris L.) in 2004-2019 was made on the territory of the Uchalinsky mining and processing plant(South Ural,Russia) contaminated with heavy metals.Relatively hi gh concentrations of copper and zinc were found in soils,roots,bark,young shoots,comparable to exceeding the maximum allowable concentrations.Despite the spatial uniformity of the heavy metal content in the stands,the tree samples significantly differed in terms of annual growth.Results suggest that the lack of nutrients and not stress from exposure to heavy metals is the main reason for relatively low growth rates on slopes of industrial wastes.It was confirmed by studying the annual growth in height of the undergrowth in habitats with different soil cover conservation.The data prove the relatively high potential of Scots pine for the natural recovery of industrial lands polluted with heavy metals by mining enterprises.

Carbon Productivity Analysis to Address Global Climate Change

Developing low-carbon economy and enhancing carbon productivity are basic approaches to coordinating economic development and protecting global environment, which are also the major ways to address climate change under the framework of sustainable development. In this paper, the authors analyze the annual rate of carbon productivity growth, the differences of carbon productivity of different countries, and the factors for enhancing carbon productivity. Consequently, the authors clarify their viewpoint that the annual rate of carbon productivity growth can be used to weigh the efforts that a country takes to address climate change, and propose policies and suggestions on promoting carbon production.

Average Annual Growth of GDP during the Eighth Five-Year Plan Period

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Multiscale wood micromechanics and size effects study via nanoindentation

Wood as a material is a natural composite with a complex hierarchically arranged structure.All scale levels of wood structure contribute to its macroscopic mechanical properties.The nature of such characteristics and deformation modes differs radically at different scale levels.Wood macroscopic properties are well studied,and the relevant information can be easily found in the literature.However,the knowledge of the deformation mechanisms at the mesoscopic level corresponding to the cellular structure of early and late wood layers of annual growth rings is insufficient.It hinders building the comprehensive multiscale model of how wood mechanical properties are formed.This paper described the results of scanning of mechanical properties of softwood and hardwood samples,such as common pine,small-leaf lime,and pedunculate oak,by means of nanoindentation(NI).The NI technique allows varying the size of deformed region within a wide range by altering maximal load(P max)applied to the indenter so that one can re-peatedly and non-destructively test wood structural components at different scale levels on the same sample without changing the technique or equipment.It was discovered that the effective microhardness(H eff)and Young’s modulus(E eff)decreased manifold with P max growing from 0.2 to 2000 mN.This drop in H effwas observed when the locally deformed region grew,and re-sulting from P max increase generally follows the rule similar to the Hall-Petch relation for yield stress,strength,and hardness initially established for metals and alloys,though obviously in those cases the underlying internal mechanisms are quite different.The nature and micromechanisms of such size effect(SE)in wood revealed using NI were discussed in this study.At P max<0.2 mN,the deformed area under the pyramidal Berckovich indenter was much smaller than the cell wall width.Hence,in this case,NI measured the internal mechanical properties of the cell wall material as long as free boundaries impact could be neglected.At P max>200 mN,the indentation encompassed several cells.The measured mechanical properties were significantly affected by bending deformation and buckling collapse of cell walls,reducing H effand E effsubstantially.At P max≈1-100 mN,an indenter interacted with different elements of the cell structure and capillary network,resulting in intermediate values of H effand E eff.Abrupt changes in H effand E effat annual growth ring boundaries allow accurate measuring of rings width,while smoother and less pronounced changes within the rings allow identification of earlywood and latewood layers as well as any finer changes during vegetation season.The values of ring width measured using NI and standard optical method coincide with 2%−3%accuracy.The approaches and results pre-sented in this study could improve the understanding of nature and mechanisms lying behind the micromechanical properties of wood,help to optimize the technologies of wood farming,subse-quent reinforcement,and utilization,as well as to develop new highly informative techniques in dendrochronology and dendroclimatology.

Vegetation Recovery in Karst Areas in Central Guizhou, China

Due to the unique environment of karst landscapes, there are many uncertainties regarding the recovery of vegetation following human disturbance. Through standard wood parsing and growth ring investigation in Puding county in Guizhou province, China, we studied the process of vegetation restoration in karst areas. According to our results, during the recovery of karst vegetation height increases and ground diameter enlargement of tree layers occurred. Increases in the height and ground diameter followed logarithmic and growth curves, respectively. The development time of trees showed continuity, and growth points were randomly distributed. However, with large propagule quantities, vegetation can be directly restored and developed into a secondary high forest without a grass filling stage, and the recovery time is shortened.

Vegetative Storage Protein with Trypsin Inhibitor Activity Occurs in Sapindus mukorassi,a Sapindaceae Deciduous Tree

A vegetative storage protein （VSP） with trypsin inhibitor activity in a deciduous tree, Sapindus mukorassi, was characterized by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western-blot, immuno-histochemical localization, light- and electro-microscopy, together with analysis of proteinase inhibitor activity of the purified VSP in vitro. There were two proteins with molecular masses of about 23 and 27 kDa in a relatively high content in the bark tissues of terminal branches of S. mukorassi in leafless periods. The proteins decreased markedly during young shoot development, indicating their role in seasonal nitrogen storage. Immuno-histochemical localization with the polyclonal antibodies raised against the 23 kDa protein demonstrated that the 23 kDa protein was the major component of protein inclusions in protein-storing cells. The protein inclusions were identified by protein-specific staining and should correspond to the electron-dense materials in different forms in the vacuoles of phloem parenchyma cells and phloem ray parenchyma cells under an electron microscope. So, the 23 kDa protein was a typical VSP in S. mukorassi. The 23 and 27 kDa proteins shared no immuno-relatedness, whereas the 23 kDa protein was immuno-related with the 22 kDa VSP in lychee and possessed trypsin inhibitor activity. The 23 kDa protein may confer dual functions： nitrogen storage and defense.