Few studies have evaluated the application of biochar to forest ecosystems and their responses under field conditions. We manually spread grounded biochar on the forest floor, at rates of 0 (control), 5, and 10 Mg ha⁻¹ (C0, C5 and C10, respectively), of an oak forest in central Japan to test the effects of biochar on tree growth and productivity. The relative growth rate of the diameter at breast height (dbh) of canopy oak trees (dbh > 20 cm) significantly increased in C10 compared with that of the control (C0), but not in C5, in the second to third years after application. Despite the increasing growth rate of canopy trees, foliage production (NPP_F) and woody production (NPP_W) did not respond to biochar application. Conversely, the production of reproductive organs (NPP_R, mainly oak acorns) increased in line with the biochar application rate gradients (1.04 ± 0.09 Mg ha⁻¹ yr⁻¹ in C0, 1.30 ± 0.08 Mg ha⁻¹ yr⁻¹ in C5, and 1.47 ± 0.13 Mg ha⁻¹ yr⁻¹ in C10). Since the contribution of NPP_R to total NPP was fairly small, there were no significant differences in total NPP (=NPP_W + NPP_F + NPP_R) for C5 (14.57 ± 0.20 Mg ha⁻¹ yr⁻¹) or C10 (16.11 ± 0.73 Mg ha⁻¹ yr⁻¹) compared with the control (15.07 ± 0.48 Mg ha⁻¹ yr⁻¹).

The structural complexity, especially canopy and gap structure, of old‐growth forests affects the spatial variation of soil respiration (Rs). Without considering this variation, the upscaling of Rs from field measurements to the forest site will be biased. The present study examined responses of Rs to soil temperature (Ts) and water content (W) in canopy and gap areas, developed the best fit modelof Rs and used the unique spatial patterns of Rs and crown closure to upscale chamber measurements to the site scale in an old‐growth beech‐oak forest. Rs increased with an increase in Ts in both gap and canopy areas, but the effect of W on Rs was different between the two areas. The generalized linear model (GLM) analysis identified that an empirical model of Rs with thecoupling of Ts and W was better than an exponential model of Rs with only Ts. Moreover, because of different responses of Rs to W between canopy and gap areas, it was necessary to estimate Rs in these areas separately. Consequently, combining the spatial patterns of Rs and the crown closure could allow upscaling of Rs from chamber‐based measurements to the whole site in the present study.

In response to severe vegetation degradation caused by sika deer in Japan, it is important to understand the habitat use trends of the sika deer and sympatric Japanese serows to promote the management and conservation of both species and their habitats. This study used camera traps to examine the trends of habitat use of the two sympatric ungulates in the Kuraiyama Experimental Forest (KEF) at Gifu University. We set camera traps at 20 sites and evaluated the number of individuals photographed for three years. Additionally, we surveyed several environmental factors around the camera trap sites to determine the relationship between species prevalence and habitat features. Both species were photographed at all sites, and some habitat use trends were observed. The deer used the west side of the valley, whereas the serows used the east, with clearer trends further observed in summer. Both ungulates avoided snow cover in winter and used steeper slopes and ridges in several seasons. With the current increase in the deer population, niche overlap between the two species may occur in the common place preferred by both species; therefore, careful monitoring of their relationships and their changes should be continued in the future.

（要旨）．ニホンジカ個体数推定のためのHarvest-based modelsにおける適切なモデル設計の検討．Harvest-based models（HBMs）を用いて野生動物の適切な個体数推定値を得るためには，モデルの構造とデータの特性を理解することが必要である．これらに対する理解が不十分な場合，適切な推定値を得られないリスクが大きくなる．本研究では，狩猟メッシュを単位とした空間解像度の高いHBMsを複数構築してニホンジカ個体数の推定を試み，モデル構造とデータの質が個体数推定値に及ぼす影響を明らかにすることを目指した．データとして，岐阜県が収集したモニタリングデータと，筆者らが収集した観測データを用いた．モデル構造（観測モデルにおける過分散の考慮の有無）とデータ（追加観測データの有無）の組み合わせにより，4つのHBMsを構築し個体数推定を試みた．その結果，4つのモデルのうち，精度の低いデータに対する観測モデルのみに過分散を設定した2つのモデルでは妥当なニホンジカ個体数が推定された．一方，すべての観測モデルで過分散を考慮した他の2つのモデルではパラメータは収束せず，また個体数推定値は過大であった．本研究の結果から，ある時点で利用可能なデータからHBMsを用いて野生動物の個体数を適切に推定するためには，モデル構造とデータの特性に対する理解が不可欠であることが確認された．