Differential photosynthetic adaptation between size-classes of Spruce and Fir juveniles help to explain the co-existence of the two species.

Background/Question/Methods 
_Abies sachalinensis_ (Sakhalin Fir) and _Picea glehnii_ (Glehn’s Spruce) are major components of the sub-boreal forests of Hokkaido, Japan. Similar Spruce-Fir forests can be found in many other places in the northern hemisphere and will probably be impacted by global warming. Therefore, detailed knowledge of these species’ physiology and life-history strategies at different growth stages is important to understand present communities and to support reliable prediction of possible consequences of global climate change. 
Accordingly, the objective of this study was to establish relations between community dynamics, life-history strategies and photosynthetic adaptation of these species, on different developmental stages. 
The study is taking place on a sub-boreal forest plot in north Japan (N 44º 19’, E 142º 15’). Twenty shade-growing individuals of both species were divided into two height classes: seedlings, if height < 50cm; and saplings, if height > 100cm. The canopy coverage over each individual was assessed by analyzing hemispherical photography and average light incidence. Leaf pigments are being analyzed by chromatography. Light response curves and chlorophyll fluorescence are being measured seasonally, except in winter. Results are analyzed through General Linear Models. The study period was from spring 2009 to summer 2010. 
Results/Conclusions 
Results show an inversion of the photosynthetic adaptation between seedlings and saplings, and also between species. _Picea_ seedlings and _Abies_ saplings have greater total chlorophyll content and higher photosynthetic rates than _Picea_ saplings and _Abies_ seedlings. As a consequence, the superior competitor between similar sized individuals of both species appears to change between size-classes, with _Abies_ presenting higher photosynthetic rates at the sapling class and _Picea_ at the seedling class. Nevertheless, no significant growth has been observed in any of the groups until now. Results also disagree with some of the previously reported photosynthetic characteristics of these species, with _Picea_ seedlings displaying more traits usually associated with shade adaptation than _Abies_ seedlings.
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Case report: Laparoscopic gastrojejunostomy for duodenal atresia with situs inversus and preduodenal portal vein: a report of two cases

Congenital duodenal atresia with situs inversus is occasionally accompanied by a preduodenal portal vein (PDPV), which is incidentally diagnosed during surgery. Duodenoduodenostomy is the most common and effective treatment. However, some patients require other anastomoses. Here, we present two cases of laparoscopic gastrojejunostomy for congenital duodenal atresia with situs inversus and PDPV and describe the reason for selecting gastrojejunostomy. The optimal surgical strategy is patient specific and should be determined based on the patient's general and physical condition

Simulating the carbon balance of a temperate larch forest under various meteorological conditions

<p>Abstract</p> <p>Background</p> <p>Changes in the timing of phenological events may cause the annual carbon budget of deciduous forests to change. Therefore, one should take such events into account when evaluating the effects of global warming on deciduous forests. In this article, we report on the results of numerical experiments done with a model that includes a phenological module simulating the timing of bud burst and other phenological events and estimating maximum leaf area index.</p> <p>Results</p> <p>This study suggests that the negative effects of warming on tree productivity (net primary production) outweigh the positive effects of a prolonged growing season. An increase in air temperature by 3°C (5°C) reduces cumulative net primary production by 21.3% (34.2%). Similarly, cumulative net ecosystem production (the difference between cumulative net primary production and heterotrophic respiration) decreases by 43.5% (64.5%) when temperatures are increased by 3°C (5°C). However, the positive effects of CO₂enrichment (2 × CO₂) outweigh the negative effects of warming (<5°C).</p> <p>Conclusion</p> <p>Although the model was calibrated and validated for a specific forest ecosystem, the implications of the study may be extrapolated to deciduous forests in cool-temperate zones. These forests share common features, and it can be conjectured that carbon stocks would increase in such forests in the face of doubled CO₂and increased temperatures as long as the increase in temperature does not exceed 5°C.</p

Formation of a Structure of Exponentially Forking Branches with a Steady-state Amount of Current-year Shoots in a Hardwood Tree Crown

Forking branches are a structural pattern characterizing a tree species. For a tree species, as a sessile organism, the forking structure is essential for gaining solar energy by spreading leaves in lighter spaces as quickly as possible. The structure is an outcome of a process in which a mother shoot of a branch produces multiple daughter shoots, and thus allows a tree to exponentially increase the amount of leaves available for photosynthetic production. On the other hand, in closed hardwood forests, tree crowns are so close to each other that there is very little space for "exponential" expansion of tree crowns [8]. How can the nature of branch forking, which appears to result in an exponential increase of leaf amount, be consistent with crown development in closed hardwood stands where crown expansion is limited due to a lack of available space? To answer such a question, analyses of demographic (birth and death) and morphological patterns of annual shoots (the portion of shoots elongated during a year) in tree crowns are useful, since they can clarify how the shoot population in a crown develops and is maintained [1, 2,3,5,6, 7,9, 10,11,12,13]. Here, we begin by showing an example of the structural pattern of a branch as observed in the top canopy of a closed hardwood forest. We then show how the observed pattern can be formed by introducing a model simulating demographic and structural patterns of the annual shoots

Stable Foliage Cluster (FC), a Basic Unit of the Crown Structure of Tree Species and Its Application to Modeling of Tree and Forest Structure: Configuration of the FC Model

The "foliage cluster (FC) model" shows that the size (the amount of leaves, number of yearly shoots and total twig length), turnover time, and branching (i.e., forking) structure of a twig becomes stable in the top of the crown in an oak species by forming a "stable FC" [1]. A stable FC can be treated as a basic component of the crown structure and as an alternative to individual leaf or current-year shoot. The FC model is composed of several equations approximating the branching structure of twigs. Differences in size and branching morphology among twigs are represented by differences in values of the parameters of the equations. We described details of our analyses of data taken from real twigs and applied to the equations implemented in the FC model

Allometric and growth data of an evergreen oak, Quercus glauca, in a secondary broadleaved forest

The evergreen oak Quercus glauca often dominates secondary broadleaved forests in Western Japan. It is regarded as a mid-successional species, whose diameter and height growth fall between those of early- and late-successional species. Despite the ecological importance of this evergreen oak in the secondary succession of the evergreen broadleaved forest zone in Japan, tree-felling data that allow estimations of tree mass and leaf area from non-destructive measurements are lacking. This paper provides stem growth data, read from tree rings on disks sampled from 13 Q. glauca stems, and their allometric data. The samples were collected in 1994 from the Ginkakuji-san National Forest, Kyoto City, Japan. Allometric data comprised data on stem age, diameter at breast height, diameter at 10% height, tree height, height of the lowest living branch, height of the lowest living leaf in the crown, volume of the main stem, squared stem diameter just below the lowest living branch, total leaf area of the stem, dry weight of the total leaves, dry weight of all branches, dry weight of the main stem, total aboveground dry weight, mean relative photosynthetic photon flux density (PPFD) above the crown, mean relative PPFD below the crown, crown projection area, and specific leaf area. These data can be helpful for estimating the biomass and leaf area index of a Q. glauca stand by enabling the derivation of allometric relationships between non-destructive measurements (such as stem diameter at breast height, and tree height) and tree mass or leaf area. Diameters (including bark thickness) at ground height and above (at 0.5- or 1-m intervals) for each stem are also provided. Stem growth data were based on tree-ring reads from disks taken from heights of 0.0 and 0.3 m, and at 0.5-m (stem height = 7 m) intervals above that. Stem volume growth derived from these tree-ring data can be converted into stem mass growth if combined with an analysis of the allometric data, which may serve as a useful resource for the estimation of carbon fixation by evergreen oaks in relation to global climate change

Patterns of Branch Growth and Death in Crowns of Sakhalin Spruce, Picea glehnii (F. Schmidt) Mast

The development of crown architecture strongly affects tree growth and survival. Growth and death of primary branches (those branching off from the main stem) and secondary branches (those from a primary branch) in the lowest part of the crown were investigated for Picea glehnii in an even-aged plantation. Probability of death of a primary branch decreased as the length between its basal location and the crown base (L-CB) increased (p = 0.04), but this probability was not significantly related to the relative photosynthetic photon flux density (rPPFD) above the primary branch (p = 0.18). The probability of producing one or more current-year shoots on a primary branch increased with increasing rPPFD above the primary branch (p = 0.01); however, this probability was unrelated to L-CB (p = 0.29). Secondary branches at the distal part of a primary branch produced more current-year shoots and exhibited a lower probability of death than proximal branches (p < 0.01), probably because rPPFD above the distal secondary branches was greater than the proximal branches (p < 0.01). Our results suggest that, while local light conditions are relevant to shoot production and shoot death on a primary branch, the death of an entire primary branch may be related to some morphological attributes concerning the length to the crown base

Relationships of tree height and diameter at breast height revisited: analyses of stem growth using 20-year data of an even-aged Chamaecyparis obtusa stand

Stem diameter at breast height (DBH) and tree height (H) are commonly used measures of tree growth. We examined patterns of height growth and diameter growth along a stem using a 20-year record of an even-aged hinoki cypress (Chamaecyparis obtusa (Siebold & Zucc.) Endl.) stand. In the region of the stem below the crown (except for the butt swell), diameter growth rates (ΔD) at different heights tended to increase slightly from breast height upwards. This increasing trend was pronounced in suppressed trees, but not as much as the variation in ΔD among individual trees. Hence, ΔD below the crown can be regarded as generally being represented by the DBH growth rate (ΔDBH) of a tree. Accordingly, the growth rate of the stem cross-sectional area increased along the stem upwards in suppressed trees, but decreased in dominant trees. The stem diameter just below the crown base (D_[CB]), the square of which is an index of the amount of leaves on a tree, was an important factor affecting ΔDBH. D_[CB] also had a strong positive relationship with crown length. Hence, long-term changes in the D_[CB] of a tree were associated with long-term changes in crown length, determined by the balance between the height growth rate (ΔH) and the rising rate of the crown base (ΔH_[CB]). Within the crown, ΔD's were generally greater than the rates below the crown. Even dying trees (ΔD ≈ 0 below the crown) maintained ΔD > 0 within the crown and ΔH > 0 until about 5 years before death. This growth within the crown may be related to the need to produce new leaves to compensate for leaves lost owing to the longevity of the lower crown. These results explain the different time trajectories in DBH-H relationships among individual trees, and also the long-term changes in the DBH-H relationships. The view that a rise in the crown base is strongly related to leaf turnover helps to interpret DBH-H relationships