Leaf survival of woody plants in deciduous broad-leaved forests. 2. Small trees and shrubs

1984 ◽  
Vol 62 (12) ◽  
pp. 2551-2556 ◽  
Author(s):  
Kihachiro Kikuzawa
Keyword(s):  
Adaptive Strategy ◽  
The Other ◽  
Forest Understory ◽  
Time Duration ◽  
Understory Species ◽  
Green Leaves ◽  
Leaf Emergence ◽  
Open Site ◽  
Leaf Survival ◽  
Trees And Shrubs

Leaf survival of 29 species of small trees and shrubs was described in and around deciduous broad-leaved forests in Hokkaido, northern Japan. Twenty-four species had green leaves in the summer (summer green) and the other five species had green leaves in winter. Among the latter, three species were evergreen, one had green leaves in the winter and no leaves in the summer (winter green), and the other had two types of shoots: evergreen and summer green (heteroptosis). In summer-green species of the understory, both leaf emergence and leaf fall lasted only a short time. Duration of leaf emergence was long in open-site species and was intermediate in gap species. Leaf survival can be considered as part of the adaptive strategy of each species. The leaves of understory species emerged in a flush; that pattern could be adaptive to the strongly seasonal illumination of the forest floor. Evergreen and winter-green habits, as well as heteroptosis, were also assumed to be adaptive to life in the understory of deciduous broad-leaved forests, since full sunlight in early spring can be utilized by their overwintering leaves. Leaf survival of gap species was presumed to be more flexible than that of forest understory species. Leaf survival of open-site species was considered to be a strategy to occupy the available open spaces as widely as possible.

Allocation de biomasse et d'énergie chez deux espèces d'Aster (Asteracées) de milieux contrastants et chez leur hybride naturel

1988 ◽  
Vol 66 (9) ◽  
pp. 1687-1692
Author(s):  
Line Lapointe ◽  
Jean-Pierre Simon
Keyword(s):  
Resource Allocation ◽  
Lower Energy ◽  
Reproductive Effort ◽  
The Other ◽  
Forest Understory ◽  
Total Biomass ◽  
Natural Hybrid ◽  
Understory Species ◽  
Biomass Resource ◽  
Allocation Patterns

Patterns of allocation of biomass and calorie energy were investigated for 3 years in several populations of the following taxa: Aster acuminatus, A. nemoralis, and their natural hybrid Aster × blakei. Aster acuminatus, a forest understory species, allocates more biomass and energy to foliage and reproductive effort than the other two taxa. Aster nemoralis, a bog species, allocates more resources to stems and rhizomes than A. acuminatus and, although average total biomass values were lower, tissues had higher caloric values. For Aster × blakei, two groups of populations showing morphological introgression to either parent were also correlated with resource allocation patterns. Caloric and biomass resource allocation patterns of populations of the three taxa did not vary significantly over the 3-year study period, except for A. acuminatus where biomass was significantly lower in 1979 than in the other 2 years. Populations showing higher absolute biomass values had organs with lower energy values. However, when these values were expressed as percentages, the patterns of allocation of biomass and energy were not differentiated within each species. [Translated by the journal]

scholarly journals Plasmodium infection decreases fecundity and increases survival of mosquitoes

2012 ◽  
Vol 279 (1744) ◽  
pp. 4033-4041 ◽  
Author(s):  
J. Vézilier ◽  
A. Nicot ◽  
S. Gandon ◽  
A. Rivero
Keyword(s):  
Life History ◽  
Insecticide Resistance ◽  
Life History Traits ◽  
Experimental System ◽  
Adaptive Strategy ◽  
Genetic Variations ◽  
The Other ◽  
Plasmodium Infection ◽  
Trade Off ◽  
The One

Long-lived mosquitoes maximize the chances of Plasmodium transmission. Yet, in spite of decades of research, the effect of Plasmodium parasites on mosquito longevity remains highly controversial. On the one hand, many studies report shorter lifespans in infected mosquitoes. On the other hand, parallel (but separate) studies show that Plasmodium reduces fecundity and imply that this is an adaptive strategy of the parasite aimed at redirecting resources towards longevity. No study till date has, however, investigated fecundity and longevity in the same individuals to see whether this prediction holds. In this study, we follow for both fecundity and longevity in Plasmodium- infected and uninfected mosquitoes using a novel, albeit natural, experimental system. We also explore whether the genetic variations that arise through the evolution of insecticide resistance modulate the effect of Plasmodium on these two life-history traits. We show that (i) a reduction in fecundity in Plasmodium- infected mosquitoes is accompanied by an increase in longevity; (ii) this increase in longevity arises through a trade-off between reproduction and survival; and (iii) in insecticide-resistant mosquitoes, the slope of this trade-off is steeper when the mosquito is infected by Plasmodium (cost of insecticide resistance).

Agroforestry: The North American Perspective

2021 ◽  
Author(s):  
Sarah T. Lovell ◽  
Harold E. "Gene" Garrett
Keyword(s):  
Alley Cropping ◽  
Indigenous Communities ◽  
Environmental Benefits ◽  
Forest Understory ◽  
Herbaceous Plants ◽  
Ecological Knowledge ◽  
Specialty Crops ◽  
Wide Range ◽  
Trees And Shrubs ◽  
Edible Products

Agroforestry has a long, rich history that is rooted in activities practiced by indigenous communities around the world. Native peoples were known to gather fruits, nuts, and understory herbs from the forest, based on their deep ecological knowledge of the natural system, and they often cultivated preferred species. For modern applications, agroforestry can be defined as the intentional integration of trees and shrubs with crops or livestock to create a multifunctional system with a wide range of benefits. In temperate regions, agroforestry is characterized by six key practices: (1) alley cropping—planting rows of trees with a companion crop grown between the rows; (2) forest farming—growing high-value specialty crops in the shaded forest understory; (3) riparian buffers—protecting water resources such as streams with a zone of trees, shrubs, and herbaceous plants; (4) silvopasture—combining trees, forage, and livestock for multiple products; (5) windbreaks—planting rows of trees and shrubs to protect crops or livestock from wind and to reduce soil erosion; and (6) urban food forests—integrating trees, shrubs, and herbaceous plants that provide edible products for the good of the community. The environmental benefits of agroforestry have been widely studied and continue to be a source of great interest. Most recently, the potential for agroforestry to contribute to climate change adaption and mitigation is being explored. While the science of agroforestry has been influenced to a great extent by the field of ecology and related disciplines, social science dimensions are increasingly captured through the study of adoption behaviors, preferences, and cultural benefits. The investigation of the role of economic and policy drivers is critical to understanding strategies to motivate landowners to adopt these practices at a level that would expand agroforestry into the mainstream. Landscape-level planning and design could provide a vision and a pathway for a broader transformation to a system that encourages perennial habitats including specialty crops that supply edible products. Such a strategy could place agroforestry more directly into the growing call to support regional food systems and positive human health outcomes. This article focuses on the trends and directions in agroforestry research primarily in North America, with emphasis on developments in the early 21st century.

scholarly journals Allometric Equations for the Aboveground Biomass of Selected Common Eastern Hardwood Understory Species

2010 ◽  
Vol 27 (4) ◽  
pp. 160-165 ◽  
Author(s):  
Yvette L. Dickinson ◽  
Eric K. Zenner
Keyword(s):  
Aboveground Biomass ◽  
Dry Weight ◽  
Vaccinium Corymbosum ◽  
Allometric Equations ◽  
Forest Understory ◽  
Rosa Multiflora ◽  
Basal Diameter ◽  
Understory Species ◽  
Elaeagnus Umbellata ◽  
Fit Index

Abstract Allometric equations were formulated for predicting the aboveground biomass of six groups of forest understory species (Elaeagnus umbellata Thunb.], blueberry [Vaccinium angustifolium Aiton, Vaccinium corymbosum L., and Vaccinium pallidum Aiton], hawthorn [Crataegus spp.], honeysuckle [Lonicera spp.], multiflora rose [Rosa multiflora Thunb.], and viburnum [Viburnum acerifolium L. and Viburnum dentatum L.]) common to Eastern hardwoods using basal diameter and/or height. As measured by fit index, basal diameter or height alone explained between 51 and 93% of the variation in oven-dry weight; this increased to 75‐96% when both basal diameter and height were used as predictors. Data were collected at four sites throughout Pennsylvania, but an evaluation of the importance of site as a blocking factor found site not to be statistically significant; therefore, the equations presented here may be used in a variety of forested sites within the greater mid-Atlantic region.

A New Concept of a Large-Workspace Small-Size Bending Bellow Actuator

2008 ◽  
Author(s):  
Alon Wolf ◽  
Ga´bor Ko´sa
Keyword(s):  
Energy Source ◽  
Shear Modulus ◽  
The Other ◽  
Energy Sources ◽  
Time Duration ◽  
Bending Effect ◽  
Output Torque ◽  
High Elasticity ◽  
Two Factors ◽  
Actuation Devices

Ask a mechanical designer, especially those dealing with robotics, what are the two main limitations when designing a new autonomous small mechanism. The answer will most likely be the need for better small-size actuation devices and better and smaller energy sources. Indeed, these two factors impose most of the constraints to designers, reflected in the size of the device, the forces it can apply, its achievable workspace, and the time duration it can work when not connected to a permanent energy source. Usually these parameters are in conflict with each other, that is, a small motor has somewhat low output torque and power, while a motor that can generate a large amount of torque is usually large in size and consumes a lot of power. Consequently, every mechanism designer is eager to design a small actuator that generates a large amount of torque while it simultaneously consumes a reasonable amount of energy. This report explains our efforts in developing an inflatable actuator having a small size yet can apply relatively large torque where at the same time can cover a large workspace. The inflatable actuator is shaped as a bellow which is composed of two materials with different shear modulus—one has high elasticity and the other low. By applying pressure inside the bellow, each of the materials tends to deform according to Hooke’s law, resulting in the bending effect due to the elongation differences between the two materials which are constrained to deform simultaneously. We describe the mechanical concept of the bellow actuator; we also provide an analytical model for the bellow deformation. Experimental results for verification of the model are also presented.

Systematic Wood Anatomy of Cornaceae and Allies

IAWA Journal ◽  
1998 ◽  
Vol 19 (1) ◽  
pp. 43-97 ◽  
Author(s):  
S. Noshiro ◽  
P. Baas
Keyword(s):  
Wood Anatomy ◽  
Cladistic Analysis ◽  
The Other ◽  
Infrageneric Classification ◽  
Diversity Pattern ◽  
Quantitative Characters ◽  
Cladistic Analyses ◽  
Trees And Shrubs ◽  
Remarkable Agreement

The wood anatomy of Comaceae, Alangiaceae, Garryaceae, and Nyssaceae constituting the Comales in the sense of Cronquist (1981, 1988) is described in great detail and subjected to a cladistic analysis. A microscopic identification key to the woods studied is given. The alliance includes seventeen genera, mostly of trees and shrubs, very rarely herbs. Although wood anatomically fairly homogeneous, variation exists in both qualitative and quantitative characters. Some of the latter show distinct latitudinal trends within individual genera, and character states have only been recognised taking their latitudinal dependencies into account. The character states ultimately recognised in these continuously varying quantitative characters coincide with intergeneric or intersectional gaps. The cladistic analysis based on a datamatrix with twentyone characters (Table 3) and using Cereidiphyllum, Daphniphyllum, and Hamamelis as outgroups yielded a strict consensus tree with a quadrichotomy with two monophyletic clades, Hydrangea panieulata (a representative of the closely allied Hydrangeaceae) and Daphniphyllum (Fig. 81). One weakly supported clade includes Alangium, Camptotheea, Cornus, Curtisia, Davidia, Diplopanax, Mastixia, and Nyssa without any robust lineages among them. The other genera, Aralidium, Aueuba, Corokia, Garrya, Griselinia, Helwingia, Melanophylla and Toricellia, constitute a second, well-supported clade. Two Hydrangea taxa included in the analysis nest in the second clade and a basal branching respectively. The wood anatomical diversity pattern thus supports a family concept of Comaceae including Cornus, Curtisia, Diplopanax, Mastixia, Alangiaceae, and Nyssaceae, and exclusion of the genera in the other clade. There is remarkable agreement between some of these wood anatomical r~sults and recent cladistic analyses of rbcL sequences by Xiang and co-workers. The infrageneric classification of Cornus, Alangium and Nyssa is also discussed.

Regrowth of forest understory species following seasonal burning

1988 ◽  
Vol 66 (1) ◽  
pp. 150-155 ◽  
Author(s):  
Marguerite A. Flinn ◽  
Ross W. Wein
Keyword(s):  
Fold Increase ◽  
Forest Stand ◽  
Forest Understory ◽  
Stem Number ◽  
Tree Seedling ◽  
Vaccinium Angustifolium ◽  
Understory Species ◽  
Number Of Stems ◽  
Maianthemum Canadense ◽  
Vaccinium Myrtilloides

Small experimental plots in mixed-wood stands of the Acadian Forest were burned in the spring, summer, and autumn to obtain an estimate of the regrowth potential of common forest understory species. The number of stems was measured before burning and then monthly for 5 months thereafter. Supportive experiments on seasonal transplanting were conducted at the same time to determine regrowth potential after interspecific competition had been removed. Regrowth potential of species varied among seasonal burning treatments as expected and was strongest for Maianthemum canadense, Vaccinium myrtilloides, Andromeda glaucophylla, Vaccinium angustifolium, Viburnum cassinoides, and Betula populifolia. These species, which showed a 10-fold increase in stem number, could compete successfully with tree seedling number and composition and thus ultimately alter forest stand composition.

scholarly journals Carbohydrate Accumulation and Flowering-related Gene Expression Levels at Different Developmental Stages of Terminal Shoots in Litchi chinensis

HortScience ◽  
2014 ◽  
Vol 49 (11) ◽  
pp. 1381-1391 ◽  
Author(s):  
Hai-Fang Yang ◽  
Hye-Ji Kim ◽  
Hou-Bin Chen ◽  
Jillur Rahman ◽  
Xing-Yu Lu ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Floral Induction ◽  
The Other ◽  
Expression Level ◽  
Carbohydrate Accumulation ◽  
Expression Levels ◽  
Green Leaves ◽  
Yellowish Green ◽  
Flowering Locus ◽  
Dark Green

Litchi trees flower at the apex of terminal shoots. Flowering is affected by the maturity of terminal shoots before growth cessation occurs during the winter. In this study, we focused on changes of flowering in three important cultivars, Guiwei, Feizixiao, and Huaizhi, from Dec. 2012 to Mar. 2013 under natural winter conditions. Flowering rate, carbohydrate accumulation, and expression of the flowering-related genes were determined at three different developmental stages of terminal shoots with dark green, yellowish green and yellowish red leaves, respectively. The results showed that the total soluble sugar and starch contents in the dark green leaves were the highest, whereas those in the yellowish red leaves were the lowest. Trees with dark green terminal shoots had the highest flowering rates, whereas those with yellowish green or yellowish red shoots had relatively lower flowering rates. SPAD was highest in dark green leaves and lowest in yellowish red leaves at the start of the trial. The SPAD value of yellowish red leaves slightly increased but did not reach the levels of the dark green leaves, whereas levels of the other leaf stages remained fairly constant. Expression level of the litchi homolog FLOWERING LOCUS C (LcFLC), the floral inhibitor in yellowish red leaves, increased from 16 Jan., whereas that in dark green leaves declined to a level lower than the yellowish red leaves on 4 Feb. Expression level of the litchi homolog CONSTANTS (LcCO), the floral promoter in dark green leaves, was higher than that of yellowish red leaves before 26 Jan. Expression level of the litchi homolog FLOWERING LOCUS T 2 (LcFT2), encoding florigen, was higher in dark green leaves than in the other two leaf types. Our results suggest that terminal shoots should be matured and leaves should turn green for successful flowering. Mature leaves had higher expression levels of the floral promoter and florigen. In litchi production, leaves of the terminal shoots (potential flowering branches) should be dark green during floral induction and differentiation stages, and winter flushes should be removed or killed.

scholarly journals ANALYSING STUDENT TOURIST MOVEMENT BASED ON THE UTILITY MAXIMISATION IN DESIGNING TOUR PACKAGE IN JOHOR BAHRU

2019 ◽  
Vol XLII-4/W16 ◽  
pp. 205-214
Author(s):  
I. A. Farid ◽  
M. F. Abdul Khanan ◽  
H. A. Umar ◽  
Z. Ismail
Keyword(s):  
Movement Pattern ◽  
Vital Role ◽  
Tourism Industry ◽  
Point Of View ◽  
The Other ◽  
Time Duration ◽  
Foreign Exchange Earning ◽  
Wealthy Country ◽  
Utility Maximisation ◽  
Maximum Utility

Abstract. Tourism industry has played a vital role in the economic development of Malaysia by driving influx of people, capital and commodities into a potentially wealthy country. Tourism also contributed to a foreign exchange earning of most South East Asian countries including Malaysia. The aim of this paper is to analyse and understand the tourist movement pattern from utility maximisation point of view in reference to the spatial pattern of tour package design in Johor Bahru. Tourist movements from one destination to the other solely depends on the tourist attractions sites available in the area and this corresponds to tourist decision on where, when, how and what time to move from one attraction site to the other. The workflow of this study until the final product is the geospatial map of the tour package that has been statistically analyse from the design questionnaire issued to students on tourism aspects. The method used in identifying and determining the utility maximisation of the arrival time and duration time for each attraction is the mode model. From the statistical result, data validation has been constructed to identify whether the result obtain is significantly accepted or fit by using the elementary statistical test. The final output has been presented in various graph to identify the maximum utility for the arrival and time duration for tour package. *For example, tour package G contains Hutan Bandar, Johor Zoo, Johor Grand Palace, Jalan Tan Hiok Nee Bangunan Kedai Lama and Bazar Karat as the listed attractions together with their corresponding arrival times and durations of time spent.

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