Reproduction of salal (Gaultheriashallon) under forest canopy

1990 ◽  
Vol 20 (1) ◽  
pp. 91-100 ◽  
Author(s):  
F. L. Bunnell
Keyword(s):  
Sexual Reproduction ◽  
Forest Canopy ◽  
Vegetative Reproduction ◽  
Resource Limitation ◽  
Shoot Density ◽  
Physiological Integration ◽  
Forest Canopies ◽  
Plant Persistence ◽  
Crown Closure ◽  
Optimality Models

Sexual and vegetative reproduction of salal (Gaultheriashallon Pursh) was measured under forest canopies of different closure. Sexual reproduction occurred only at ≤33% closure; vegetative reproduction occurred under sparse and dense closure. Crown closure influenced sexual reproduction primarily through interception of radiation and associated reductions in salal vigour. Irradiance had a greater influence on the mode of reproduction than did shoot density, and allocation of total reproductive effort (sexual plus vegetative) was contrary to optimality models, but consistent with resource limitation. No shoot <5 years old flowered; shared costs of flowering indicated physiological integration among salal shoots. Vegetative reproduction was negatively associated with age (r2 = 0.95), and 85% of the space occupied after 9 years of growth was occupied during the first 3 years. Under canopy the spatial pattern of salal shoots was better adapted to maintain plant persistence than to colonize new areas. Implications of salal's rates and modes of reproduction to forest and wildlife management are noted.

scholarly journals Forest Canopy Can Efficiently Filter Trace Metals in Deposited Precipitation in a Subalpine Spruce Plantation

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 318 ◽  
Author(s):  
Siyi Tan ◽  
Hairong Zhao ◽  
Wanqin Yang ◽  
Bo Tan ◽  
Kai Yue ◽  
...  
Keyword(s):  
Trace Metals ◽  
Human Disturbance ◽  
Forest Canopy ◽  
Subalpine Forest ◽  
Forest Canopies ◽  
Closed Canopy ◽  
Filtering Efficiency ◽  
One Year ◽  
The One ◽  
Filtering Effect

Trace metals can enter natural regions with low human disturbance through atmospheric circulation; however, little information is available regarding the filtering efficiency of trace metals by forest canopies. In this study, a representative subalpine spruce plantation was selected to investigate the net throughfall fluxes of eight trace metals (Fe, Mn, Cu, Zn, Al, Pb, Cd and Cr) under a closed canopy and gap-edge canopy from August 2015 to July 2016. Over the one-year observation, the annual fluxes of Al, Zn, Fe, Mn, Cu, Cd, Cr and Pb in the deposited precipitation were 7.29 kg·ha−1, 2.30 kg·ha−1, 7.02 kg·ha−1, 0.16 kg·ha−1, 0.19 kg·ha−1, 0.06 kg·ha−1, 0.56 kg·ha−1 and 0.24 kg·ha−1, respectively. The annual net throughfall fluxes of these trace metals were −1.73 kg·ha−1, −0.90 kg·ha−1, −1.68 kg·ha−1, 0.03 kg·ha−1, −0.03 kg·ha−1, −0.02 kg·ha−1, −0.09 kg·ha−1 and −0.08 kg·ha−1, respectively, under the gap-edge canopy and 1.59 kg·ha−1, −1.13 kg·ha−1, −1.65 kg·ha−1, 0.10 kg·ha−1, −0.04 kg·ha−1, −0.03 kg·ha−1, −0.26 kg·ha−1 and −0.15 kg·ha−1, respectively, under the closed canopy. The closed canopy displayed a greater filtering effect of the trace metals from precipitation than the gap-edge canopy in this subalpine forest. In the rainy season, the net filtering ratio of trace metals ranged from −66.01% to 89.05% for the closed canopy and from −52.32% to 33.09% for the gap-edge canopy. In contrast, the net filtering ratio of all trace metals exceeded 50.00% for the closed canopy in the snowy season. The results suggest that most of the trace metals moving through the forest canopy are filtered by canopy in the subalpine forest.

scholarly journals Reproductive Strategies of the Seagrass Zostera japonica Under Different Geographic Conditions in Northern China

2020 ◽  
Vol 7 ◽  
Author(s):  
Shidong Yue ◽  
Xiaomei Zhang ◽  
Shaochun Xu ◽  
Yu Zhang ◽  
Peng Zhao ◽  
...  
Keyword(s):  
Sexual Reproduction ◽  
Asexual Reproduction ◽  
Reproductive Strategies ◽  
Geographic Location ◽  
Dry Weight ◽  
Northern China ◽  
Shoot Density ◽  
Zostera Japonica ◽  
Sexual And Asexual Reproduction ◽  
Density And Biomass

Seagrasses form a unique group of submerged marine angiosperms capable of both sexual and asexual reproduction. The amounts of sexual and asexual reproduction differ within some species relying on geographic location and environmental factors. Here, we studied the reproductive strategies of different geographic Zostera japonica populations, S1 and S2 at Swan Lake lagoon (SLL), and H1 and H2 at Huiquan Bay (HQB), in northern China. The duration of flowering at SLL was longer than at HQB, whereas flowering initiation at HQB occurred earlier than at SLL. In addition, the timing of seed maturation at HQB occurred earlier than at SLL. The allocation to sexual reproduction at SLL was greater than at HQB. The maximum potential seed production was greatest at S1 (22228.52 ± 8832.46 seeds ⋅ m–2), followed by S2 (21630.34 ± 9378.67 seeds ⋅ m–2), H2 (7459.60 ± 1779.33 seeds ⋅ m–2), and H1 (2821.05 ± 1280.57 seeds ⋅ m–2). The seasonal changes in total shoot density and biomass were small at HQB. There was a relatively large number of overwintering shoots at HQB because of the higher average temperature during winter. The allocation to sexual reproduction was lower than at SLL, and no seedlings were observed at HQB during our study. Thus, the population of Z. japonica at HQB was maintained by asexual reproduction. Compared with HQB, the biomass of overwintering shoots at SLL was less than 30 g dry weight ⋅ m–2. The Z. japonica at SLL relied on asexual and sexual reproduction to maintain the population. The results show the necessity of understanding local reproductive strategies before starting restoration and management projects. The study provides fundamental information and guidance for the conservation and restoration of seagrass beds.

Niche differentiation between two rhizomatous plant species: Typha latifolia and Typha angustifolia

1982 ◽  
Vol 60 (1) ◽  
pp. 46-57 ◽  
Author(s):  
James B. Grace ◽  
Robert G. Wetzel
Keyword(s):  
Sexual Reproduction ◽  
Shallow Water ◽  
Surface Area ◽  
Leaf Surface ◽  
Vegetative Reproduction ◽  
Typha Latifolia ◽  
Morphological Characteristics ◽  
Niche Differentiation ◽  
Typha Angustifolia ◽  
Leaf Surface Area

Morphological characteristics and biomass allocation were examined for two species of Typha in a small pond. Typha latifolia differed from T. angustifolia in having shorter leaf height, wider leaves, greater leaf surface area, greater allocation to leaves, greater number of smaller rhizomes, greater allocation to vegetative reproduction, smaller allocation to sexual reproduction, and fewer number of flowering plants. For both species, those plants growing in deeper water had taller leaves, a greater allocation to leaves, and a decreased allocation to sexual and vegetative reproduction. Previous studies of these populations have demonstrated that these two species are segregated according to water depth with T. latifolia being competitively superior in shallow water (less than 15 cm) but T. angustifolia having the potential to grow in deeper water than T. latifolia. Results from this study indicate that T. latifolia is competitively superior in shallow water because of its greater leaf surface area but that T. angustifolia's tall, narrow leaves and large rhizome storage permit it to grow in deeper water than T. latifolia. The greater amount of sexual reproduction in T. angustifolia is correlated with its more restricted distribution and fugitive nature.

Multi-angular observation of forest canopy reflectance based on a hyperspectral UAV imaging platform

2020 ◽  
Author(s):  
Feng Qiu ◽  
Qian Zhang
Keyword(s):  
Forest Canopy ◽  
Vegetation Indices ◽  
Canopy Structure ◽  
Distribution Patterns ◽  
Background Information ◽  
Canopy Reflectance ◽  
Bidirectional Reflectance ◽  
Forest Canopies ◽  
Ground Distance ◽  
Observation Method

&lt;p&gt;Forest canopy reflectance varies with solar and observation geometries and shows distinct anisotropic characteristics. The bidirectional reflectance distribution function (BRDF) of forest canopies is influenced by canopy structure, leaf biochemistry and background reflectance. Multi-angular remote sensing observations of forest canopies provide much more information about canopy structure and background information compared with the nadir observations. The development of unmanned aerial vehicle (UAV) provides great opportunities for multi-angular observations in forests. We developed a solid method to obtained bidirectional reflectance of forest canopies based on a hyperspectral UAV imaging platform in this study. With this multi-angular observation method, we obtained canopy reflectance images with the view zenith angle (VZA) varying from 60&amp;#176; (forward) to 60&amp;#176; (backward) at fixed interval (10&amp;#176;), as well as the hotspot and darkspot images in the principle plane in conifer forests. Since the single pixel with very high spatial resolution (around 10 cm) in the UAV images are not representative for the study of the whole forest canopy, several pixels in the central of each images were selected and averaged to determine the canopy reflectance. Variations of the averaged reflectance with ground distance represented by the selected pixels were analyzed and the optimum ground distance for study the multi-angular forest canopy reflectance was determined. The observed canopy reflectance peaks at the hotspot and clear images of the hotspot are observed. The sensitivities of canopy reflectance to VZAs vary with spectral bands. The reflectance at red bands near 680 nm are most sensitive to VZA. Some common used vegetation indices, such as NDVI, EVI, MTCI, PRI, also vary greatly with VZAs and demonstrate different spatial distribution patterns. The observations fit well with the 4-Scale geometric-optical model simulations. The multi-angular observation methods based on UAV platform have the advantages of efficient and effective in multi-angular observation with higher flexibility in VZA adjustment and lower cost, compared with the airborne or spaceborne sensors. This multi-angular observation method is very useful for study the BRDF and canopy structural and biochemical characteristics of forests and has great potential in forestry and ecological studies.&lt;/p&gt;

scholarly journals Comparison of Seven Inversion Models for Estimating Plant and Woody Area Indices of Leaf-on and Leaf-off Forest Canopy Using Explicit 3D Forest Scenes

2018 ◽  
Vol 10 (8) ◽  
pp. 1297 ◽  
Author(s):  
Jie Zou ◽  
Yinguo Zhuang ◽  
Francesco Chianucci ◽  
Chunna Mai ◽  
Weimu Lin ◽  
...  
Keyword(s):  
Forest Canopy ◽  
Estimation Algorithm ◽  
Area Ratio ◽  
Forest Canopies ◽  
Tree Species Composition ◽  
Area Index ◽  
Inversion Model ◽  
Segment Size ◽  
Clumping Index ◽  
Index Estimation

Optical methods require model inversion to infer plant area index (PAI) and woody area index (WAI) of leaf-on and leaf-off forest canopy from gap fraction or radiation attenuation measurements. Several inversion models have been developed previously, however, a thorough comparison of those inversion models in obtaining the PAI and WAI of leaf-on and leaf-off forest canopy has not been conducted so far. In the present study, an explicit 3D forest scene series with different PAI, WAI, phenological periods, stand density, tree species composition, plant functional types, canopy element clumping index, and woody component clumping index was generated using 50 detailed 3D tree models. The explicit 3D forest scene series was then used to assess the performance of seven commonly used inversion models to estimate the PAI and WAI of the leaf-on and leaf-off forest canopy. The PAI and WAI estimated from the seven inversion models and simulated digital hemispherical photography images were compared with the true PAI and WAI of leaf-on and leaf-off forest scenes. Factors that contributed to the differences between the estimates of the seven inversion models were analyzed. Results show that both the factors of inversion model, canopy element and woody component projection functions, canopy element and woody component estimation algorithms, and segment size are contributed to the differences between the PAI and WAI estimated from the seven inversion models. There is no universally valid combination of inversion model, needle-to-shoot area ratio, canopy element and woody component clumping index estimation algorithm, and segment size that can accurately measure the PAI and WAI of all leaf-on and leaf-off forest canopies. The performance of the combinations of inversion model, needle-to-shoot area ratio, canopy element and woody component clumping index estimation algorithm, and segment size to estimate the PAI and WAI of leaf-on and leaf-off forest canopies is the function of the inversion model as well as the canopy element and woody component clumping index estimation algorithm, segment size, PAI, WAI, tree species composition, and plant functional types. The impact of canopy element and woody component projection function measurements on the PAI and WAI estimation of the leaf-on and leaf-off forest canopy can be reduced to a low level (<4%) by adopting appropriate inversion models.

Throughfall and stemflow chemistry under deciduous and coniferous forest canopies in south-central Ontario

1994 ◽  
Vol 24 (6) ◽  
pp. 1089-1100 ◽  
Author(s):  
A.J. Neary ◽  
W.I. Gizyn
Keyword(s):  
Dry Deposition ◽  
Forest Canopy ◽  
Coniferous Forest ◽  
Base Cations ◽  
Ion Sources ◽  
Regression Technique ◽  
Forest Canopies ◽  
South Central ◽  
Internal Sources ◽  
Scavenging Efficiency

By measuring incident precipitation, throughfall, and stemflow chemistry, the roles of coniferous- and deciduous-dominated forest canopies as a source of and sink for ions in precipitation were examined. A regression technique for distinguishing between external (dry deposition) and internal (canopy leaching) sources of ions in the throughfall flux was evaluated. The effect of seasonal changes in the forest canopy on throughfall and stemflow chemistry was also examined. Throughfall comprised 74 and 84%, respectively, of the hydrologic flux at the coniferous and deciduous sites. Sulphate fluxes were highest at the coniferous site during both growing and dormant seasons, suggesting either a higher scavenging efficiency of the needles for atmospheric SO42−, or higher SO42− leaching from the foliage. The deciduous site neutralized acidic inputs, as demonstrated by its net negative H+ flux year round. The buffering capacity of the coniferous forest was exceeded by the higher amount of acid interception by the canopy. Nitrate behaved conservatively and base ions were exported from the canopy. Stemflow contributions of ions, although low, were generally higher than the contribution of stemflow to the hydrologic flux (2–3%). Independent dry deposition measurements for the growing season, when compared with net SO42− flux, overestimated dry deposition collected by the deciduous canopy, but were comparable to the flux at the coniferous site. These data suggest that dry SO2−SO42− deposition may be responsible for all SO42− enrichment seen in throughfall at these sites. A regression technique for separating internal and external ion sources in throughfall yielded inconsistent results, and attributed virtually all ion enrichment to internal sources. Problems with false assumptions and spurious correlations are discussed. We conclude that this method is not satisfactory for separating ion sources. Seasonal patterns in throughfall chemistry are present. During the growing seasons bases exchange for H+ and are exported similarly with SO42−. Hydrogen retention mirrors SO42− export. Base cations (particularly K+) are leached from the canopy primarily during senescence, but from the stem of the tree primarily during the dormant period. This was most evident at the deciduous site. Chloride behaved in a similar manner, while NH4+ and H+ were retained during the senescent period.

Effect of prolonged vegetative reproduction of olive tree cultivars (Olea europaea L.) in mitochondrial homoplasmy and heteroplasmy

Genome ◽  
2003 ◽  
Vol 46 (3) ◽  
pp. 377-381 ◽  
Author(s):  
Angel García-Díaz ◽  
Ricardo Oya ◽  
Antonio Sánchez ◽  
Francisco Luque
Keyword(s):  
Mitochondrial Genome ◽  
Sexual Reproduction ◽  
Olea Europaea ◽  
Vegetative Reproduction ◽  
Intergenic Spacer Region ◽  
Olea Europaea L ◽  
Chloroplast Genomes ◽  
Mitochondrial Region ◽  
Olive Trees ◽  
Olea Europaéa

The inheritance of mitochondrial and chloroplast genomes does not follow Mendelian laws, but proceeds by vegetative segregation. Most organisms show organelle homoplasmy, which is probably produced and maintained during sexual reproduction. We have tested the effect of prolonged vegetative multiplication in the maintenance of mitochondrial homoplasmy and the generation of heteroplasmy in cultivated olive trees, Olea europaea L. Seven trees, each representing a different variety of olive, were analysed by the study of an intergenic spacer region of the mitochondrial genome. A very high level of heteroplasmy was detected in all cases. We found multiple genome variants of the sequence analysed. The frequency of genomes with no changes in the spacer region was 11.5%. This means that 88.5% of genomes contain at least one change. The same spacer mitochondrial region was sequenced in several clones from four olive trees of a second generation of sexually reproduced trees. In these trees, many clones were identical and had no changes, which represents a clear reduction of the heteroplasmy (p < 0.001). Therefore, this work supports the relevance of the role of sexual reproduction in the maintenance of mitochondrial homoplasmy and also shows that mutations accumulate in a non-coding sequence of the mitochondrial genome when vegetative propagation is maintained for a long period of time.Key words: mitochondrial genome, homoplasmy, heteroplasmy, olive trees, vegetative reproduction, sexual reproduction.

MVP: a model to simulate the spatial patterns of photosynthetically active radiation under discrete forest canopies

2004 ◽  
Vol 34 (6) ◽  
pp. 1192-1203 ◽  
Author(s):  
Conghe Song ◽  
Lawrence E Band
Keyword(s):  
Spatial Patterns ◽  
Photosynthetically Active Radiation ◽  
Forest Canopy ◽  
Ecological Models ◽  
Computationally Efficient ◽  
Forest Canopies ◽  
Active Radiation ◽  
Beer's Law ◽  
Beer’S Law ◽  
The Mean

The spatial patterns of photosynthetically active radiation (PAR) under forest canopies, including both its mean and spatial variation, are critical factors to numerous understory ecophysiological processes. Currently, Beer's law is the primary algorithm used in ecological models simulating PAR transmission through plant canopies, because more accurate models are too complicated to be used operationally. This study developed a simple and computationally efficient model at a stand scale to simulate both the mean and variation of PAR (MVP) under forest canopies. The model assumes that a forest canopy is composed of individual crowns distributed within upper and lower boundaries with two types of gaps: the between- and within-crown gaps. The between-crown gaps are simulated with geometric optics, and the within-crown gaps are described by Beer's law. The model accounts for the covariance of PAR in space through time, making it possible to simulate both instantaneous and daily accumulated variance of PAR. Validation with observed PAR from the boreal ecosystem–atmosphere study (BOREAS) indicates that the model captures the mean and variance of PAR under forest canopy reasonably well. MVP holds the potential to improve simulation of light interception by forest canopies as well as the treatment of canopy rainfall interception in ecological models.

Water temperature modelling in a small forested stream: implication of forest canopy and soil temperature

2000 ◽  
Vol 27 (6) ◽  
pp. 1095-1108 ◽  
Author(s):  
André St-Hilaire ◽  
Guy Morin ◽  
Nassir El-Jabi ◽  
Daniel Caissie
Keyword(s):  
Soil Temperature ◽  
Water Temperature ◽  
Forest Canopy ◽  
Deterministic Model ◽  
Heat Budget ◽  
Original Model ◽  
Small Catchment ◽  
Negative Exponential Function ◽  
Modified Model ◽  
Crown Closure

The demand for comprehensive environmental assessment of river ecosystem has increased for engineers and scientists. Accurate and versatile water temperature models are required to meet this demand. A number of hydrological models take vegetation and soil characteristics into account, but very few temperature models do. The objective of this paper is to incorporate soil temperature and vegetation as input variables in a deterministic heat budget model. The CEQUEAU hydrological and water temperature model was used to simulate water temperature in Catamaran Brook, a small catchment located in central New Brunswick. The model was modified by incorporating soil temperature as a parameter influencing the temperature of interflow, using the so-called force-restore method. Crown closure was also incorporated in the model as a factor influencing locally advected water using a negative exponential function. The modified model simulated daily water temperatures better than the original model. Root-mean-square error for a period of 5 years decreased from 2.10°C with the original model to 1.77°C with the modified model. Nash coefficient increased from 0.78 with the original model to 0.82 with the modified model. An analysis of residuals showed that the modified model is sensitive to additional parameters such as crown closure, especially for short time scales during periods of higher discharge and during extreme meteorological and hydrological events such as tropical storms.Key words: stream temperature, hydrology, deterministic model, CEQUEAU, forestry.

scholarly journals UPSCALING OF SOLAR INDUCED CHLOROPHYLL FLUORESCENCE FROM LEAF TO CANOPY USING THE DART MODEL AND A REALISTIC 3D FOREST SCENE

2017 ◽  
Vol XLII-3/W3 ◽  
pp. 107-111 ◽  
Author(s):  
W. Liu ◽  
J. Atherton ◽  
M. Mõttus ◽  
A. MacArthur ◽  
H. Teemu ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Forest Canopy ◽  
Multiple Scales ◽  
Canopy Structure ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Fluorescence Signal ◽  
Forest Canopies ◽  
Vertical Heterogeneity ◽  
Leaf Level

Solar induced chlorophyll a fluorescence (SIF) has been shown to be an excellent proxy of photosynthesis at multiple scales. However, the mechanical linkages between fluorescence and photosynthesis at the leaf level cannot be directly applied at canopy or field scales, as the larger scale SIF emission depends on canopy structure. This is especially true for the forest canopies characterized by high horizontal and vertical heterogeneity. While most of the current studies on SIF radiative transfer in plant canopies are based on the assumption of a homogeneous canopy, recently codes have been developed capable of simulation of fluorescence signal in explicit 3-D forest canopies. Here we present a canopy SIF upscaling method consisting of the integration of the 3-D radiative transfer model DART and a 3-D object model BLENDER. Our aim was to better understand the effect of boreal forest canopy structure on SIF for a spatially explicit forest canopy.

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