Sapflow measurements were carried out in a larch forest in eastern Siberia, an area of wide permafrost distribution. Canopy transpiration and canopy conductance were scaled up from these values.The objective was to analyze the relationship between environmental variables, mainly vapour pressure deficit (D), soil moisture and soil thawing rate with canopy transpiration and canopy conductance. the forest. By comparison with other studies in this region, canopy transpiration is estimated to contribute to almost 50 % of the total forest evaporation, highlighting the important role of understorey transpiration in permafrost regions. Our results show that it is not only the impermeability of permafrost with the property of keeping soil moisture in the thin active layer but it is also the slow soil thawing rate that plays the important role of controlling the amount of water available for trees roots in the upper soil layers during dry years.Interannual environmental-soil thawing rate variation and its control on transpiration from Larix cajanderi, Central Yakutia, Eastern Siberia. Permafrost regions occurring presumably in the Northern hemisphere are of special hydrological interest because of seemingly strange features of local soils and associated behavior of forest tree species, mostly larch. The authors focused on water loss of boreal forests, in Eastern Siberia typical with low precipitation, where water from thawed permafrost is important for tree survival. They applied sap flow technique and usual meteorological and soil moisture equipment for this purpose over two growing seasons (July-Sept. 2003 and 2004). Authors: Here I would like to make something very clear. Water thawed from permafrost is not used by trees, unless there has been a disturbance that has severely broken the stability of permafrost. As it can be observed in figure 4 (of the original manuscript) the active layer (soil layer that freezes in winter and thaws in summer) reaches its maximum thickness at the end of September when leave shedding has already started or water uptake from trees is already very low. Furthermore, root density below 1 meter is close to zero and thus importance of permafrost for tree survival lies not as a water source but as an impermeable layer that avoids water filtration downward. The most important point that I have probably not conveyed properly is the fact that gradual soil layers thawing (Fig. 4) allows the retention of water in the upper layers were the bulk of tree roots distribute and that this deepening shows an inter-annual variation, being slower when water supply is low so as to make more water available for (in the upper layers) tree survival.Unfortunately neither methodical nor instrumental information is provided. Authors: My deepest apologies for this. I make myself (first author) responsible for not providing the proper information. In the revised text all the methodical and instrumental information is provided.So it is not clear e.g., how solar radiation was measured (e.g. by a home-made sol...

Sap flow measurements, from July to August 2004, were coupled with micrometeorological, soil moisture, and soil temperature measurements to analyze forest water dynamics in irrigated and undisturbed (control) larch (Larix cajanderi) forest plots in eastern Siberia. Plots were irrigated with 120 mm (20 mm day -1 ) of water from 17 to 22 July. Sap flow measurements of ten trees at each plot were scaled up to daily stand canopy transpiration (E c ). Canopy transpiration at the irrigation and control plots was similar before irrigation. Forest evapotranspiration (E a ) was obtained from Ohta et al. (Agric For Meteorol 148:1941-1953 while E a in the irrigation plot was estimated based on the E c_irrig /E c_cont ratio. Rainfall during July-August was 63.4 mm but, after including water from thawing soil layers, the actual water input was 109.9 and 218.5 mm in the control and irrigation plots, respectively. Despite this large difference, a corresponding difference in E c (and E a ) was not observed [42.6 (61.5) mm and 46.4 (71.8) mm in control and irrigation plots, respectively]. Daily canopy conductance (g c ) increased as long as moisture was well supplied in the upper soil layers and evaporative demand was high. Soil moisture and rainfall contribution to E a was 36.9 and 24.6 mm in the control plot and 34.5 and 37.3 mm in the irrigation plot, respectively. Water supply from soil thawing layers in the control plot and high runoff (105.6 mm) rates in the irrigation plot accounted for the similarity in water dynamics. Under increased precipitation, the forest used less soil water stored from previous growing seasons.

We studied how the dominant factor affecting stem volume growth changes during stand development in a monoclonal stand of Cryptomeria japonica D. Don. Stem analysis was used to compare growth history of trees in an unthinned plot (closed canopy) and a thinned plot (open canopy). In the unthinned plot, the dominant factor affecting stem volume growth was basal area (BA) before canopy closure, whereas neighborhood competition index (CI) was the dominant factor after canopy closure. In contrast, the dominant factor affecting stem volume in the thinned plot was BA throughout stand development. Spearman's rank correlation coefficient between BA and CI continued to increase after canopy closure and size rank among individuals became increasingly fixed. Our results indicated that stem volume growth shifts from size-dependent to competitiondependent growth at canopy closure. The apparent correlation between tree size and growth rate observed in many previous studies may be the result of competitionmediated positive feedback between size and growth.

A future increase in heavy precipitation events is predicted in boreal regions. An irrigation experiment was conducted in Taiga forest in eastern Siberia to evaluate the effect of heavy precipitation on greenhouse gas ([GHG] CO 2 , CH 4 , and N 2 O) fluxes in the soil. The GHG fluxes on the soil surface were measured using a closed-chamber method and GHG production rates in the mineral soil were estimated using the concentration-gradient method based on Fick's law. Irrigation water (20 mm day ) was applied continuously for 6 days (120 mm in total; the same amount as summer precipitation in this region). Greenhouse gas production rates in the organic layer (O-layer) were defined as the difference between the GHG fluxes and the GHG production rates in the mineral soil. Carbon dioxide flux was measured both in root-intact (R s ) and trenched plots (R mw ). The root respiration rate (R r ) was calculated as the difference between R s and R mw . Considering the root distribution in the soil, we regarded the CO 2 production rate in the mineral soil to be the microbial respiration rate in the mineral soil (R mm ) and microbial respiration rate in the O-layer (R mo ) as the difference between R mw and R mm . Irrigation increased both soil temperature and moisture in the irrigated plot. The R s , CH 4 flux and N 2 O flux during the irrigation period were higher in the irrigated plot than that in the non-irrigated plot (P < 0.05; mean R s ± standard deviation [SD] ) were 171 ± 20 and 109 ± 11, mean CH 4 flux ± SD (lg C m )2 h )1 ) were )5.4 ± 4.1 and )14.0 ± 6.5, and mean N 2 O flux ± SD (lg N m )2 h )1) were 1.6 ± 1.6 and 0.2 ± 1.1, respectively). Soil moisture had a positive effect on R mm and CH 4 production rate in the O-layer, a negative effect on R r , and did not affect R mo , the CH 4 production rate in the mineral soil or the N 2 O production rates in both the O-layer and the mineral soil. Soil temperature had a positive effect on R r and R mo . The increment of global warming potential of the soil mainly resulted from an increase in microbial respiration rates. Future changes in precipitation patterns in this region would accelerate decomposition of the soil organic matter.

and reforestation is being researched for cost reduction by using logging machines in reforestation. In this study, we researched clearcutting and reforestation productivity and cost with the vehicle logging system in three areas that included five gentle slope forest stands in Nagano Prefecture. As the results revealed labor productivity of m man-day in clearcutting operations, we expect productivity of about m man-day with similar systems. In our site preparations, the grapple loader showed higher productivity than human power, and use of the loader reduced cost to as compared to human power. The forwarding operation of carrying seedlings was reduced to of the usual cost. The planting productivity of the containerized trees was significantly higher than that of bare-root trees, but also higher in cost. To balance cost cutting with efficiency, we expect a lower price for containerized trees.