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1.
An attempt was made to examine the possible connection between the various ratios of calcium/aluminum (Ca/Al) in the nutrient
solution of plant cultures and the active oxygen scavenging system of hinoki cypress (Chamaecyparis obtusa) seedlings. The hinoki cypress seedlings were transferred to nutrient solutions containing 5 mM AlCl3 together with various concentrations of Ca(NO3)2 in pots containing glass beads and Teflon tips. The activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase
(APX) and glutathione reductase (GR) in the needles were estimated at several stages during the 7-day treatment. The samples
treated with the lower Ca/Al solutions show the highest SOD activities. The activities of APX and GR, both of them involved
in the ascorbate-glutathione cycle, showed the same tendency with decrease to higher Ca/Al ratio. These results indicate that
rhizospheric Ca might compete with Al and ameliorate Al toxicity on and in the roots, the Al stress is not transformed to
the needles after a few days, and the ascorbate-glutathione cycle in the hinoki cypress needles might fluctuate and be suppressed
by the rhizospheric Al stress during the 7 days.
This work was supported in part by funding from the Japan Science & Technology Corporation, the CREST program 1996–2001, and
the Center for Forest Decline Studies. 相似文献
2.
Tadashi Ogawa Chisato Matsumoto Chisato Takenaka Takafumi Tezuka 《Journal of Forest Research》2000,5(2):81-85
The effect of CA(NO3)2 on the active oxygen scavenging system in hinoki cypress (Chamaecyparis obtusa) seedlings cultured in a nutrient solution containing aluminum was examined. The hinoki cypress seedlings were transferred
to nutrient solutions containing 5 mM AlCl3 together with various concentrations of Ca(NO3)2 in pots containing glass beads and Teflon tips. The growth in height and dry matter allocation to each organ was little influenced
over a period of 12 weeks by either Al or the concentration of Ca(NO3)2. The activity of superoxide dismutase (SOD) in the needles was stimulated by Al, and the effect of Al was lowered significantly
by simultaneous application of 25 mM Ca(NO3)2. At week 1, the activity of catalase (CAT) in the needles was increased by Al, but the effect was no longer observed at week
12. The Al concentration in the roots was increased by treatment with Al, whereas the Al concentration in needles was not.
These results indicate that rhizospheric Al stress stimulates antioxidative enzyme activities in hinoki cypress needles and
the activation of the enzymes is suppressed by addition of Ca. The transmission of Al stress to the needles, which induced
a change in the enzyme activity, is not caused by the transfer of the Al ion itself from roots to needles.
This work was supported in part by funding from the Japan Science and Technology Corporation, the CREST program 1996–2001,
and the Center for Forest Decline Studies. 相似文献
3.
We evaluated the protective effects of floor cover against soil erosion in three types of forest located on steep slopes
under a humid climate: 22- and 34-year-old Chamaecyparis obtusa (hinoki), 34-year-old Cryptomeria japonica (sugi), and 62-year-old Pinus densiflora (red pine) stands. We measured sediment transport rates (sediment mass passing through one meter of contour width per millimeter
of rainfall), using sediment traps, before and after removing floor cover. Raindrop splash erosion was dominant in the experimental
stands. Floor cover percentage (FCP) during the preremoval stage varied from 50% to 100% among the four stands, and sediment
transport rates ranged from 0.0079 to 1.7 g m−1 mm−1. The rates increased to 1.5–5.6 g m−1 mm−1 immediately after removing floor cover, and remained high throughout the experiment. The presence of physical cover near
the ground has a crucial effect on sediment transport on forested slopes. The protective effect ratio (the ratio of the sediment
transport rate in a control plot to that in the removal plot) in a young hinoki stand, in which the FCP decreased markedly,
was 0.3 at most, which is close to the rate for bare ground. The protective effect ratio in the red pine stand was ≤0.003.
We concluded that the protective effect of floor cover in undisturbed forests in Japan differs by over two orders of magnitude,
based on comparisons with previous studies.
Received: March 11, 2002 / Accepted: August 16, 2002
Present address: Department of Forest Site Environment, Forestry and Forest Products Research Institute, Ibaraki 305-8687 Japan Tel. +81-298-73-3211;
Fax +81-298-74-3720 e-mail: miura@affrc.go.jp
Present address: Department of Forest Site Environment, Forestry and Forest Products Research Institute, Ibaraki 305-8687 Japan Tel. +81-298-73-3211;
Fax +81-298-74-3720 e-mail: miura@affrc.go.jp
Acknowledgments This study was supported by the Research Council of the Ministry of Agriculture, Forestry, and Fisheries, of Japan. We thank
H. Ujihara, S. Ujihara, and M. Ogasawara in Otoyo, Kochi, who provided the experimental stands used in this study. We also
thank K. Hirai, S. Kuramoto, E. Kodani, and the rest of the staff at the Shikoku Research Center, Forestry and Forest Products
Research Institute, for their help in conducting the experiments.
Correspondence to:S. Miura 相似文献
4.
Takuya Kajimoto Akira Osawa Yojiro Matsuura Anatoly P. Abaimov Olga A. Zyryanova Kazuma Kondo Naoko Tokuchi Muneto Hirobe 《Journal of Forest Research》2007,12(2):103-112
We present results of individual-based root system measurement and analysis applied for Larix gmelinii trees growing on the continuous permafrost region of central Siberia. The data of root excavation taken from the three stands
were used for the analyses; young (26 years old), mature (105 years old), and uneven-aged over-mature stand (220 years old).
In this article, we highlight two topics: (1) factors affecting spatio-temporal pattern of root system development, and (2)
interactions between aboveground (i.e., crown) and belowground (i.e., root) competition. For the first topic, the detailed
observation of lateral roots was applied to one sample tree of the overmature stand. The tree constructed a superficial (<30 cm
in depth) and rather asymmetric root system, and each lateral root expanded mainly into elevated mounds rather than depressed
troughs. This indicated that spatial development of an individual root system was largely affected by microtopography (i.e.,
earth hummocks). For these lateral roots, elongation growth curves were reconstructed using annual-ring data, and annual growth
rates and patterns were compared among them. The comparison suggested that temporal root system development is associated
with differences in carbon allocation among the lateral roots. For the second topic, we examined relationships between individual
crown projection area (CA) and horizontal rooting area (RA) for the sample trees of each stand. RA was almost equal to CA
in the young stand, while RA was much larger (three or four times) than CA in the mature and overmature stands. Two measures
of stand-level space occupation, crown area index (aboveground: CAI; sum of CAs per unit land area) and rooting area index
(belowground: RAI; sum of RAs), were estimated in each stand. The estimates of RAI (1.3–1.8 m2 m−2) exceeded unity in all stands. In contrast, CAI exceeded unity (1.3 m2 m−2) only in the young stand, and was much smaller (<0.3 m2 m−2) in the two older stands. These between-stand differences in RAI–CAI relationships suggest that intertree competition for
both aboveground and belowground spaces occurred in the young stand, but only belowground competition still occurred in the
two older stands. Based on this finding, we hypothesized that competition below the ground may become predominant as a stand
ages in L. gmelinii forests. Methodological limitations of our analysis are also discussed, especially for the analysis using the two indices
of space occupation (CAI, RAI). 相似文献
5.
Yutaka Kataoka Makoto Kiguchi Takeshi Fujiwara Philip D. Evans 《Journal of Wood Science》2005,51(5):531-536
Low density wood is more rapidly eroded than denser wood when exposed to the weather, possibly because it is more susceptible
to photodegradation. Fourier transform infrared microscopy was used to examine: (1) the depth of photodegradation in earlywood
and latewood of sugi (Japanese cedar) and earlywood of hinoki (Japanese cypress) exposed for up to 1500 h to artificial sunlight
emitted by a xenon lamp (375 W/m2 within the 300 to 700 nm spectral range); and (2) the relationship between the density of wood tissues and depth of photodegradation.
The depth of photodegradation varied between species (sugi and hinoki) as well as within a growth ring (sugi earlywood and
latewood), and there was an inversely proportional relationship between depth of photodegradation and wood density. These
findings may explain why low density earlywood is more rapidly eroded than latewood during weathering, and more generally,
why there is an inverse relationship between the density of wood species and their rate of erosion during artificial and natural
weathering.
Part of this work was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004 相似文献
6.
Yuliati Indrayani Tsuyoshi Yoshimura Yoshiyuki Yanase Yuji Imamura 《Journal of Wood Science》2007,53(3):239-248
Five Japanese timbers, four timbers from the USA, and one Malaysian timber were evaluated for their resistance to the invasive
dry-wood termite Incisitermes minor (Hagen) using laboratory choice and no-choice feeding tests with holed specimens. The highest survival rates of I. minor in both the heartwood and sapwood no-choice feeding tests were more than 70% after 3 months. When offered sapwood and heartwood
choice feeding tests and the combined choice feeding tests, the highest survival rates of I. minor were more than 75% after 3 months. With regards to the percentage of wood mass losses in the no-choice and choice feeding
tests, karamatsu (Larix leptolepsis), buna (Fagus crenata), and Douglas fir (Pseudotsuga menziesii) were classified as “resistant” species among the ten sapwood specimens. In the heartwood no-choice and choice feeding tests,
the resistant species were buna, karamatsu, Douglas fir, sugi (Cryptomeria japonica), akamatsu (Pinus densiflora), and western red cedar (Thuja plicata). The ranking of the resistance of the ten commercial timbers against I. minor was buna > karamatsu > sugi > western red cedar > Douglas fir > rubber > western hemlock > hinoki > spruce. 相似文献
7.
Katsuaki Ishii 《Journal of Forest Research》2002,7(2):99-104
Hinoki cypress (Chamaecyparis obtusa) is one of the most important timber resource forest trees in Japan. Because seed production from a seed orchard of hinoki
cypress is not constant every year, micropropagation from a limited amount of material is useful. Up to now, the conventional
tissue culture method using solid medium has been used. Here a new method using liquid culture in tubes rotated vertically
is described. Shoot primordium of hinoki cypress was inoculated in Campbell and Durzan’s (CD) liquid medium containing different
cytokinins (6-benzylaminopurine (BAP), Zeatin, thidiazurone (TDZ)), and the container tubes were rotated vertically around
the axis at 2 times / min. Culture room temperature was 25°C and light condition was 16 h photoperiod per day of fluorescent
lamps. Zeatin at 1μM concentration was the best for maintaining the shoot primordium production and TDZ induced callus on the surface of the
shoot primordia. After shoot primordium multiplication in the liquid culture, they were transplanted to agar medium for shoot
elongation. A high concentration of agar (up to 16 g/L) or AVF (anti vitrification factor from Dr. Nairn, 1995) was effective
to prevent vitrification of the shoots. Transformation of shoot primordium was done using particle bombardment with vectors
containingβ-glucuronidase (GUS) gene or herbicide resistance gene (bar). Positive result for transient transformation was observed with the histo-chemical study for transformation with GUS. Integration
of a useful herbicidebar gene into the shoot primordium culture system was also tried and stably transformed plants were obtained. This is the first
report of stable transformation of Japanese conifer using practically useful gene.
The generous supply of AVF-B from Dr. B.J. Nairn, Tasman Forestry, NZ is also appreciated. 相似文献
8.
Transport rates of surface materials on steep forested slopes induced by raindrop splash erosion 总被引:1,自引:0,他引:1
We used small (25 cm) sediment traps to evaluate the properties of surface material transport on steep slopes under humid
temperate conditions in the Shikoku district of Japan. We sampled ten stands ofChamaecyparis obtusa (hinoki),Cryptomeria japonica (sugi),Pinus densiflora (red pine), and deciduous hardwood forest. Transport rates were estimated by dividing the amount of mass transported by the
mass of rainfall during a given period. These rates varied widely among the ten stands: 0.0065–0.31 g m−1 mm−1 (a difference of two orders of magnitude) for fine earth, 0.00017–0.97 (four orders) for gravel, and 0.020–0.24 (one order)
for litter. The transport rates in young hinoki stands with a low floor cover percentage (FCP) showed no seasonal changes.
The transport rates changed by one or two orders of magnitude in hardwood forests with clear seasonal changes in FCP, as well
as in juvenile and middle-aged hinoki and sugi stands, where understory floor cover increased and decreased seasonally. Rainfall
intensity, however, showed no positive effects on transport rates, even in stands that had changing transport rates. The rates
were mostly determined by forest type. We demonstrate that transport rate is an inherent property of a forest that reflects
floor cover conditions and indicates the potential of surface material transport.
This study was supported by the Research Council in the Ministry of Agricuture, Forestry and Fisheries, Japan. 相似文献
9.
Delignified hinoki wood and cellulose as well as hinoki and lauan woods were carbonized at 590°C for 1 h. The dielectric properties
of these specimens were measured at 20°C in a frequency range of 20 Hz to 1 MHz. Inflection points in the dielectric constant
(ε′) versus the logarithm of frequency (log f) curves as well as in the logarithm of the electric conductivity (log σ) versus log f curves for all specimens prepared were recognized. Peaks in the dielectric loss and the imaginary part of the complex conductivity
versus the log f curves were detected in the frequency location corresponding to the inflection point in the ε′ and log σ versus log f curves. It was considered that this relaxation was responsible for the interfacial polarization observed in heterogeneous
materials because no permanent dipoles existed in the specimens carbonized above 500°C. The Cole–Cole circular arc law was
applied to account for this relaxation. Similar average relaxation times were obtained for all specimens. These results suggested
that the observed relaxation was ascribed to interfacial polarization at microscopic levels in the cell walls. 相似文献
10.
The effect of temperature upon nighttime respiration was examined on four different sized sample trees in a 17-year-old hinoki
cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) stand over two years. Seasonal changes inQ
10 values and their responses to mean temperature were investigated. On the basis of the monthly relationships between nighttime
respiration (r) and temperature inside a chamber (θ),r=r
0exp (kθ), theQ
10 value (=exp(10k)) was calculated. TheQ
10 values were high (Q
10≥3.0) in winter when mean air temperature was low, and gradually decreased toward summer (Q
10≤1.5) through spring with increasing temperature. TheQ
10 values were negatively correlated with mean air temperature. The response ofQ
10 values to mean air temperature was described by a single equation, regardless of tree size. This result, which might be characteristic
of this species, shows that respiration ofC. obtusa trees is promoted by slight increases of air temperature in winter season. On the other hand, temperature sensitivity of
total respiration reduced during growing season when ambient temperature was high. These chaning temperature sensitivity according
to seasons may depend on the seasonal change of the ratio of growth respiration to total respiration. It is concluded that
changes in temperature due to changing seasons not only change respiration rate, but also change the response of respiration
rate to temperature by shiftingQ
10 values. 相似文献
11.
The species richness of trees, shrubs and climbing plants was investigated in 41 sugi (Cryptomeria japonica D. Don) plantations of different stand age and area in southern Kyushu, southwestern Japan. Altogether 174 species were found,
of which 145 infrequent species were selected for analysis. Two groups were extracted from the species list according to their
occurrence in older (49 spp.) or younger (28 spp.) stands, the latter containing a higher percentage of climbing plants and
species with wind-dispersed seeds. In contrast, the older stand group contained major tree components typical of seminatural,
evergreen broadleaved forests in the region and was more heavily dependent on stand age, especially for species with gravity-
and frugivore-dispersed seeds, showing a gradual increase up to 60 years old. The species richness was less correlated with
edge perimeter facing seminatural forests and the years after latest thinning. The juxtaposition of plantation compartments
with stands of seminatural forest or other plantations, as well as the compartment's origin as former plantation site or a
seminatural stand, had relatively little influence on species richness. However, topographic variation was important in determining
the species composition, with valley stands having higher species richness and containing many plants typical of the regional
seminatural forests. These results suggest that (1) the major trend of species richness is determined by the presence of old
stand type species, (2) topographic variation of species richness remains even after establishment of plantations, and (3)
the normal rotation period of sugi plantations (35–40 years) may therefore be too short to conserve the maximum potential
species diversity within the working forest.
Received: June 4, 2001 / Accepted: August 26, 2002
Acknowledgments We wish to thank the staff of the Miyazaki University Forests for cooperation in the fieldwork. A part of this study was
supported by the Grant-in-Aid for Scientific Study from the Ministry of Education, Science and Culture of Japan (no. 09041071
and no. 10460068).
Correspondence to:S. Ito 相似文献
12.
In order to clarify the effects of a mixture of deciduous broad-leaved trees on soil fertility, we investigated litter biomass
accumulation, mineral soil chemical and physical characteristics, characteristics of nitrogen mineralization, and the mutual
relationships between them in Japanese cypress (Chamaecyparis obtusa) stands mixed with deciduous broad-leaved trees at different ratios (mixture ratio; MR = 0, 16, 33, 43, 100% by basal area)
in the northern Kanto region of Japan. Litter biomass in the forest floor and mineral soil was 19.1 Mg ha−1 in MR 0% and decreased approximately 60 % in MR 33%, MR 43% and MR100%. The permeability at 0–5 cm soil depth in MR100% was
twice as much as that in MR 0%. Increases in soil permeability were likely due to larger soil pores in the higher MR with
much accumulated deciduous broad-leaves. At 0–5 cm soil depth, the differences in carbon concentration among the plots were
not clear. On the other hand, carbon concentrations at 5–10 cm depth increased from 90 g kg−1 to 147 g kg−1 with increases in MR from 0% to 100%. Concentrations of exchangeable bases increased two to four times with increases in
MR from 0 to 100% at 0–10 cm depth. Soil pH (H2O) generally increased with increases in MR at each depth. The rates of net nitrogen mineralization at 0–5 cm depthin vitro increased from 25 to 87 mg kg−1 2 weeks−1 with increases in MR from 0 to 100%. However, increases in nitrification with increases in MR were not clear compared with
nitrogen mineralization. These results indicated that a mixture of deciduous broad-leaved trees in a Japanese cypress stand
was effective in preventing soil fertility decline.
This study was supported by a grant from the Showa Shell Sekiyu Fundation for Promotion of Environmental Research. A part
of this study was presented at the 7th International Congress of Ecology (1998). 相似文献
13.
Stephen Adu-Bredu Taketo Yokota Kazuharu Ogawa Akio Hagihara 《Journal of Forest Research》1997,2(1):31-37
The study was carried out in a 9-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.), stand over a span of three years from July 1992 to June 1995, primarily to predict litter production
from exteral tree dimensions by combining open-top clothtrap and clipping methods. Litter production was virtually concentrated
in October and November. Stem cross-sectional area at the crown base was proved to be the reliable predictor of litter production,
and that single regression model was evolved irrespective of year. The regression model had proportional constants of 2.696
× 10−2 and 3.540 × 10−2 kg cm−2 year−1 for leaf litter and total litter production, respectively. Utilizing the model, leaf litter production of the stand was assessed
to be 5.04, 5.12, and 4.99, and total litter production to be 6.48, 6.58, and 6.40 Mg ha−1 year−1 for the first, second and third year, respectively. Biomass increment was 6.67, 7.80, and 7.70, tree mortality was 0.15,
0.13, and 0.41, and insect grazing was 0.09, 0.05, and 0.002 Mg ha−1 year−1 for the first, second and third year, respectively. Above-groud net production was therefore 13.39, 14.55, and 14.51, Mg
ha−1 year−1, and biomass accumulation ratio (biomass/net production) was 1.86, 2.21, and 2.76 year for the first, second and third year,
respectively. Considering data from earlier studies and the results of this study, biomass accumulation ratio,BAR (year), of hinoki stands was best related to above-ground biomass,y (Mg ha−1), using the power function:BAR=0.112y
0.936. Excluding seedling stands, leaf efficiency (above-ground net production per unit leaf mass) of hinoki stands was 0.91±0.02
(SE) Mg Mg−1 year−1, irrespective of stand biomass or age. 相似文献
14.
Takuya Kajimoto Gaku Hitsuma Takashi Masaki Tatsuo Kanazashi 《Journal of Forest Research》2006,11(2):107-116
We analyzed the growth patterns of Thujopsis dolabrata var. hondai trees in an old plantation (161 years old), where no silvicultural treatments (e.g., thinning) have been conducted since
the initial planting. The analysis focused on understanding individual growth under a long-term self-thinning process, and
the stand-level stemwood production at the mature stage was evaluated. Nine canopy-layer trees and one suppressed tree were
used for the analysis of annual increments in stem diameters, heights, and stemwood volumes for a given past year using the
ring-width data. Both the diameter (at basal portion) and height of all the canopy-layer trees increased at similar rates
during the early stage (i.e., 60–70 years after planting); however, after this period, only the height growth rates declined
sharply. The annual growth rates of stemwood volume also simultaneously leveled off at the stand age of 40–60 years. Subsequently,
the patterns diverged conspicuously, e.g., the growth rates were maintained or increased in some individuals, while it gradually
decreased in the case of others until the present year. The divergence of growth pattern was likely to be triggered by intertree
competition at several decades after the onset of canopy closure. The current stemwood production of the sample trees, including
the suppressed one, was positively correlated with certain size parameters such as stem diameter at breast height and sapwood
area at a height of 4 m. Based on the diameter-base allometry, the total stand stemwood production was estimated to be about
12.8 m3 ha−1 year−1. This estimate was higher than those of some old natural T. dolabrata forests (2.0–8.6 m3 ha−1 year−1) that have been well managed by repetitive selection thinning. Furthermore, individual mean stemwood production of the study
plantation (0.03 m3 tree−1 year−1) was within the range of these natural stands (0.01–0.05 m3 tree−1 year−1). These comparisons suggested that the old T. dolabrata plantation still maintained a relatively high stemwood production potential despite the absence of artificial controls of
tree density in the past. In terms of timber production, this fact implied that a rather long rotation (>100 years) can be
applicable in the management of T. dolabrata plantations. 相似文献
15.
We investigated the biomass, vertical distribution, and specific root length (SRL) of fine and small roots in a chronosequence
of Japanese cedar (Cryptomeria japonica D. Don) plantations in Nara Prefecture, central Japan. Roots were collected from soil blocks up to 50 cm in depth in five
plantations of differing age: 4, 15, 30, 41, and 88 years old. Fine-root biomass reached a maximum (639 g m−2) in the 15-year-old stand before canopy closure, decreased in the 30-year-old stand (422 g m−2), and thereafter was stable. Except in the 30-year-old stand, fine-root biomass increased in deeper soil layers as stand
age increased, and the depth at which the cumulative biomass of fine roots reached 90% exhibited a good allometric relationship
with mean stem diameter. Both root-length density (root length per unit soil volume) and SRL decreased with soil depth in
all stands, indicating that plants mainly acquire water and nutrients from shallow soils. The highest SRL was observed in
the 4-year-old stand, but the relationship between SRL and stand age was unclear in older stands. The SRL in surface soils
seemed to decrease with increases in root-length density, suggesting that branching of the fine-root system during development
is related to density-dependent processes rather than age. 相似文献
16.
Yoshio Kijidani Yoshimitsu Fujii Keita Kimura Yoshitake Fujisawa Yuichiro Hiraoka Ryushi Kitahara 《Journal of Wood Science》2012,58(3):195-202
It was previously believed in Japan that the wood qualities of hinoki (Chamaecyparis obtusa) were superior to sugi (Cryptomeria japonica). However, few studies of wood properties such as MFA (microfibril angle of S2 layer in secondary wall of tracheid) have been completed for hinoki. Some reports have found that hinoki plus tree families have similar mechanical properties to sugi. Here we report the characteristics of MFA and density of hinoki half-sib families in a progeny test stand. There were significant differences in MFA and density between families. The wood properties of two families, Nakatsu 3 and Kanzaki 5, are stable in radial pattern and suitable for structural use. Early selection of hinoki families by MFA and density may be difficult. Effects of MFA and density on E d (dynamic modulus of elasticity) of logs differed between families. The effects of growth rate on MFA and density differed between families and also between juvenile and mature wood. The faster growth rate in Nakatsu 3 appeared to improve wood properties and increase E d of logs, although in many other families, faster growth rate had negative effects on desirable wood properties for structural use. 相似文献
17.
The effects of elevated atmospheric CO2 concentrations on the nighttime respiration were examined for two sample branches of a hinoki cypress tree (Chamaecyparis obtusa) growing in the field with an open gas exchange system for a one-year period from July 1994 to June 1995. The branches were
of a similar size and located at a similar position within the crown. One branch was subjected to an elevated CO2 concentration of 800 μmol mol−1 and the other was subjected to ambient air which had a CO2 concentration of about 370 μmol mol−1. Nighttime respiration rate was higher in elevated CO2 level than in ambient CO2 level. The relationship between nighttime respiration and the corresponding nighttime air temperature was fitted by the exponential
function in every month of the year. The segregation of regression lines between the two CO2 treatments increased gradually as the seasons progressed during the treatment period. TheQ
10 values for nighttime respiration were lower in elevated CO2 (1.9 ≤Q
10 ≤ 3.7) than in ambient CO2 (2.4 ≤Q
10 ≤ 4.5) in every month of the year. TheQ
10 was inversely related to the monthly mean nighttime air temperature in both elevated and ambient CO2. The estimated daily nighttime respiration rate under both CO2 treatments had a similar seasonal pattern, which almost synchronized with the temperature change. The respiration ratio of
elevated CO2 to ambient CO2 increased gradually from 1.1 to 1.6 until the end of the experiment. Our results indicate that the CO2 level and the temperature have a strong interactive effect on respiration and suggest that a potential increase in respiration
of branches will occur when ambient CO2 increases. 相似文献
18.
One main task of forestry is a reliable estimation of the stem form and its development applied in calculating total and log
volume. As long as process-oriented models are not available for this practical use, empirical models must serve instead.
Taper curve data of trees within stands normally show a rank maintenance,i.e., a tree which has a greater diameter than another one at a certain height, is most probably bigger at any other height, too.
This property also applies to the analysed tree species, sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa), and will be well-represented by a linear model formulation. As model parameter sets of single stands have a very limited
time validity, two approaches for future stem form prediction are discussed. The one, the centroaffine transformation of a
linear taper curve function, is not suitable for representing the time-depending change of the stem form. However, this can
be done by a linear unit taper curve model, the parameters of which are based on sample trees of stands of several age classes.
Temporary unit parameter sets are derived for sugi and hinoki and the estimated stand volumes are compared to the real ones
to evaluate the model performance, which turned out to be very good.
We would like to express our gratitude to the Japan Science and Technology Corporation for the financial promotion, which
enabled this research work. 相似文献
19.
Shuisong Zhang Changfa Chen Shouqing He Kexuan Wu Yousheng Zhan 《Frontiers of Forestry in China》2008,3(3):254-263
In the intermediate cutting intensity experiment of a Cunninghamia lanceolata plantation for 20 years, the changing pattern of natural thinning in these stands, with different intermediate cutting intensities,
was studied. The relationship between the number of trees removed by natural thinning and stand density and site conditions
was explained. The mathematical equation M = K
1·K
2 of natural thinning lines of C. lanceolata stand density management maps was tested and the relationship of diameter, height and canopy structure of stands with different
intermediate cutting intensities are proposed. Our study of natural thinning in these stands indicates that the starting and
peak periods of natural thinning in the check and slightly thinned plots were both early. The amount of thinned wood was large
and the course of thinning proceeded continuously. The three levels of thinning: the slight thinning period, the intensive
thinning period and the continued thinning period could be divided on the basis of the amount of thinned wood. Natural thinning
would be a very long process without artificial interference. The starting and peak periods of thinning in the middle and
strong intermediate felling are both late and present intermittence. Their thinning stages were not clearly evident. Through
our studies, we also discovered that stand density and site conditions had important effects on the number of dead and dying
trees, but that density was more important than site conditions. By way of tests, the relative error of the mathematical equation
of natural thinning lines of C. lanceolata stand density management maps was 3.91% and the precision was relatively high. The practical test results of the stands,
given different intermediate cutting intensities and different site indices, show that the relative error of the check plots
was 5.23%, while the relative errors of the other tested items were all < 5%, well within the allowable experimental error.
The mathematical equation was comparatively practical. The study demonstrated the distribution laws of diameter and height
classes of the stand at different intermediate cutting intensities. From this study we also obtained the growth differences
and changing dynamics of the height to the first branch, canopy length and relative canopy height of the stand at different
intermediate cutting intensities and various related patterns with an increase of stand age and proposed a mathematical model
relating stand age and the single-tree periodic volume increment.
__________
Translated from Scientia Silvae Sinicae, 2006, 42(1): 55–62 [[译自: 林业科学] 相似文献
20.
Root biomass and root distribution were studied in Entisols derived from the thick deposition of volcanic pumice on Hokkaido
Island, Japan, to examine the effect of soil conditions on tree root development. The soil had a thin (<10 cm) A horizon and
thick coarse pumiceous gravel layers with low levels of available nutrients and water. Two stands were studied: a Picea glehnii–Abies sachalinensis stand (PA stand) and a Larix kaempferi–Betula platyphylla var. japonica stand (LB stand). The allometric relationships between diameter at breast height (DBH) and aboveground and belowground biomass
of these species were obtained to estimate stand biomass. The belowground biomass was small: 30.6 Mg ha−1 for the PA stand and 24.3 Mg ha−1 for the LB stand. The trunk/root ratios of study stands were 4.8 for the PA stand and 4.3 for the LB stand, which were higher
than those from previous studies in boreal and temperate forests. All species developed shallow root systems, and fine roots
were spread densely in the shallow A horizon, suggesting that physical obstruction by the pumiceous layers and their low levels
of available water and nutrients restricted downward root elongation. The high trunk/root ratios of the trees may also have
resulted from the limited available rooting space in the study sites. 相似文献