scholarly journals Quantifying the effect of local shelter on tree growth patterns within upper treeline ecotones in the Bighorn Mountans of Wyoming.

2017 ◽  
Author(s):  
◽  
Nathan Mackley
Keyword(s):  
Spatial Pattern ◽  
Tree Growth ◽  
Growth Rates ◽  
Growth Patterns ◽  
Tree Regeneration ◽  
Annual Growth ◽  
Limiting Factor ◽  
Spatial Pattern Analysis ◽  
Tree Establishment ◽  
Moisture Retention

On Bruce Mountain in the Bighorn Mountains of Wyoming, the upper treeline ecotone has advanced upslope since 1970 and to the highest extent in at least the past 210 years. However, the mechanisms facilitating tree establishment and treeline advance during this time were distinctly different between north and south-facing slope aspects. Tree regeneration on the south-facing slope was predominantly confined to microsites in the sheltered lee of boulders where more shade, moisture retention, and protection from the wind exist. Trees on the north-facing slope colonized open alpine tundra and facilitated continued regeneration clustered in close proximity to these trees. Thus, while patterns of tree establishment and treeline advance are well understood, it remains unknown whether differences in tree growth exist between these two sites. This is relevant as other studies suggest that favorable climatic conditions for tree establishment do not correspond with periods of high annual growth rates for trees at upper treeline. The goal of this research was to determine whether distinct patterns of tree establishment influence annual growth rates of these trees. To address this, I calculated basal area increment (BAI) for all trees positioned above the upper forest border. Surprisingly, annual growth rates and corresponding BAI values were almost identical between sites since 1970. These results suggest that tree establishment may be more of a critical limiting factor to upper treeline advance than tree growth because consistent growth patterns were found irrespective of spatial pattern on opposite slope aspects. From spatial pattern analysis, tree establishment on the northern slope adheres to the known biological preferences for each of the treeline species; while the pattern of establishment on the southern slope is overridden by the availability of favorable sites (i.e. in the lee of boulders) providing needed shade and moisture retention. As the treeline is a temperature and moisture-limited ecotone, there are observed differences along the elevational gradient within the site and between species that grow open and have a higher drought tolerance compared to those that rely on shade and neighboring trees.

Two-year tree growth patterns investigated from monthly girth records using dendrometer bands in a wet evergreen forest in India

2000 ◽  
Vol 16 (3) ◽  
pp. 429-446 ◽  
Author(s):  
Raphaël Pélissier ◽  
Jean-pierre Pascal
Keyword(s):  
Growth Rate ◽  
Tree Growth ◽  
Growth Patterns ◽  
Annual Growth ◽  
Evergreen Forest ◽  
Annual Growth Rate ◽  
Growth Data ◽  
Growth Profiles ◽  
Dendrometer Bands ◽  
The Mean

With the aim of characterizing tree growth patterns, this paper re-examines the growth data of 100 selected trees belonging to 24 species that were recorded monthly in a 0.2-ha plot of a wet evergreen forest in the Western Ghats of India during the period 1980–82 using dendrometer bands. The mean growth profile, combining all of the selected trees, showed: (a) a significantly lower annual growth rate during the second year of survey which seemed to be negatively related to monsoon precipitation; (b) significant intra-annual growth variation clearly related to the regular alternation between a period of heavy rain and a quite long dry season of the monsoon climatic regime. Analysis of the variability of the individual smoothed growth profiles representing the 2-y trend of the growth data showed that: (a) the mean growth rate depended on a combination of an intrinsic endogenous variable (the structural class grouping species according to their maximum size), a tree size variable (tree diameter at breast height, dbh) and a neighbourhood variable (the number of taller neighbours in a 10-m radius); (b) the sudden change in growth rate from one year to the other was not predictable using these variables. The amplitude of the seasonal variations, investigated from the detrended growth profiles, appeared to be dependent on a combination of tree dbh and the number of taller neighbours in a 10-m radius. A co-inertia analysis of the smoothed and the detrended growth profiles indicated that the trees with fast growth also exhibited high seasonal variation. It is suggested that fast growing trees are those with favourable crown positions, which are consequently subject to high transpiration rates due to radiation and wind exposure.

scholarly journals Long term pasture growth patterns for Southland New Zealand: 1978 to 2012

2012 ◽  
pp. 147-151
Author(s):  
L.C. Smith
Keyword(s):  
New Zealand ◽  
Key Words ◽  
Growth Rates ◽  
Initial Period ◽  
Farm Management ◽  
Growth Patterns ◽  
Annual Growth ◽  
Management Systems ◽  
Summer Peak

Pasture growth rates for Southland were reported by several researchers in the late 1970s and early 1980s. However, pasture species and farm management systems have changed somewhat since then. This paper presents data from measurements at Woodlands, near Invercargill, that have been ongoing since 1977, and discusses some of the variability that has occurred over the years. Measurement of pasture growth was done using a standardised cutting method known as "rate of growth" or moving cages, with measurements every 3 weeks. Annual yields were calculated from 1 June to 31 May of the next year. The pasture growth at Woodlands is characterised by a spring-summer peak of growth followed by a deep winter trough where growth is minimal. Long-term average annual growth was 11.8 t DM/ha for older 'Ruanui' based pasture and 12.7 t DM/ ha for newer 'Nui'/'Supreme'/'Greenstone' ryegrass based pasture. However the newer pasture produced considerably more (ca.14.2 t DM/ha/year) for an initial period of 3 years, after which time the production dropped back to be similar to the old pasture (ca.12.0 t DM/ha/year). Key words. pasture growth; long-term; annual variability

On the Age and Growth Rate of Giant Cacti: Radiocarbon Dating of the Spines of Cardon (Pachycereus Pringlei)

Radiocarbon ◽  
2016 ◽  
Vol 58 (3) ◽  
pp. 479-490 ◽  
Author(s):  
Mariana Delgado-Fernández ◽  
Pedro P Garcillán ◽  
Exequiel Ezcurra
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Annual Growth ◽  
Age And Growth ◽  
Limiting Factor ◽  
Annual Growth Rate ◽  
Columnar Cacti ◽  
Rate Versus ◽  
The Mean ◽  
Pachycereus Pringlei

AbstractAge estimation has been a limiting factor in the study of giant columnar cacti. In order to test the feasibility of using radiocarbon methods to estimate the age of the giant cardon cacti (Pachycereus pringlei), we selected six sites spanning the latitudinal and precipitation range of the species in the Baja California peninsula. In each site, we selected four individuals of different heights and sampled a spine from the lowest areole in the stem. The age of the spine was estimated using 14C dating, and the mean annual growth rate of the plant was calculated dividing the height of the lead shoot by the plant’s age. Mean annual growth rate was 0.098 m/yr, with values varying between 0.03 and 0.23 m/yr. Within the range of plants sampled, mean annual growth rates were significantly correlated with the height of the plant (r2=0.82, P<0.0001), and no other site-specific variable such as precipitation or latitude was a significant predictor of mean annual growth rates. A model integrating mean growth rate versus height showed that relatively small differences in growth rates between plants accumulate during the plants’ lifetime, so that plants of similar size may have very different ages. We conclude that 14C dating provides a robust method to explore the growth and demography of columnar cacti.

scholarly journals Rural Migration and Urbanization in China: Historical Evolution and Coupling Pattern

2020 ◽  
Vol 12 (18) ◽  
pp. 7307 ◽  
Author(s):  
Yuanzhi Guo ◽  
Weifeng Qiao
Keyword(s):  
Spatial Pattern ◽  
Growth Rates ◽  
Socioeconomic Development ◽  
Rapid Development ◽  
Development Stage ◽  
Annual Growth ◽  
Spatial Distance ◽  
Rural Migration ◽  
Spatial Inequalities ◽  
Urbanization In China

Using a population dataset of China, this study analyzes the spatial pattern of rural migration and urbanization and their coupling coordination relationship and investigates the causes of their spatial heterogeneity. Results show that rural migration and urbanization from 1978 to 2017 can be divided into three stages, i.e., the recovery and development stage, the stable and rapid development stage, and the stage of promoting the citizenization of the rural migrant population. From 2000 to 2010, counties with average annual growth rates of the ratio of rural migration (GRM) ranging from 0 to 5.00% showed a spatial pattern of ubiquitous distribution, while there were significant spatial inequalities in the average annual growth rates of the urbanization rate of the residential population (GUR) and hukou-registered population (GUH). Since urbanization and rural migration are two synergistic processes, coupling coordination degrees (CCDs) between GRM and GRU as well as GRM and GUH were generally between 0.60 and 0.80. Due to the gaps in socioeconomic development, spatial distance, and the policy system, they also showed regional heterogeneity, and there were notable differences in CCD between rural migration and urbanization of residential and hukou-registered populations. Finally, we propose that China should implement targeted and people-oriented measures to guide rural migration, promote new-type urbanization, and achieve integrated urban–rural development.

scholarly journals Using Tree Growth Rates to Evaluate Urban Tree Planting Specifications

1997 ◽  
Vol 15 (2) ◽  
pp. 115-118 ◽  
Author(s):  
Barbara A. Neal ◽  
Thomas H. Whitlow
Keyword(s):  
Urban Environment ◽  
Tree Growth ◽  
Growth Rates ◽  
Tree Planting ◽  
Annual Growth ◽  
Washington Dc ◽  
Urban Tree ◽  
Natural Park ◽  
Incremental Growth ◽  
Quercus Phellos

Abstract Annual growth was measured from increment cores extracted from 105 willow oaks (Quercus phellos L.) growing in seven locations in the metropolitan Washington, DC, area. Sample sites were selected to represent a range of planting specifications. In general, annual incremental growth was least in the transplant year, followed by 3–6 years of increasing growth rates that met or exceeded growth rates in the nursery. Five of the sites supported growth rates similar to open-grown trees, in a semi-natural, park-like setting, while trees growing in an irrigated, fertilized tree lawn had substantially higher growth rates. Our findings suggest that planting specifications can overcome many of the limitations to tree growth imposed by the urban environment, at least during the first 15 years following installation.

scholarly journals Differential Trends of Qinghai Spruce Growth with Elevation in Northwestern China during the Recent Warming Hiatus

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 712
Author(s):  
Bin Wang ◽  
Pengtao Yu ◽  
Lei Zhang ◽  
Yanhui Wang ◽  
Yipeng Yu ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
Tree Growth ◽  
Growth Patterns ◽  
Limiting Factor ◽  
Suitable Habitat ◽  
Picea Crassifolia ◽  
Warming Hiatus ◽  
High Elevations ◽  
Qinghai Spruce

Tree growth strongly responds to climate change, especially in semiarid mountainous areas. In recent decades, China has experienced dramatic climate warming; however, after 2000 the warming trend substantially slowed (indicative of a warming hiatus) in the semiarid areas of China. The responses of tree growth in respect to elevation during this warming hiatus are poorly understood. Here, we present the responses of Qinghai spruce (Picea crassifolia Kom.) growth to warming using a stand-total sampling strategy along an elevational gradient spanning seven plots in the Qilian Mountains. The results indicate that tree growth experienced a decreasing trend from 1980 to 2000 at all elevations, and the decreasing trend slowed with increasing elevation (i.e., a downward trend from −10.73 mm2 year−1 of the basal area increment (BAI) at 2800 m to −3.48 mm2 year−1 of BAI at 3300 m), with an overall standard deviation (STD) of 2.48 mm2 year−1. However, this trend reversed to an increasing trend after 2000, and the increasing trends at the low (2550–2900 m, 0.27–5.07 mm2 year−1 of BAI, p > 0.23) and middle (3000–3180 m, 2.08–2.46 mm2 year−1 of BAI, p > 0.2) elevations were much weaker than at high elevations (3300 m, 23.56 mm2 year−1 of BAI, p < 0.01). From 2000–2013, the difference in tree growth with elevation was much greater than in other sub-periods, with an overall STD of 7.69 mm2 year−1. The stronger drought conditions caused by dramatic climate warming dominated the decreased tree growth during 1980–2000, and the water deficit in the 2550–3180 m range was stronger than at 3300 m, which explained the serious negative trend in tree growth at low and middle elevations. After 2000, the warming hiatus was accompanied by increases in precipitation, which formed a wetting–warming climate. Although moisture availability was still a dominant limiting factor of tree growth, the relieved drought pressure might be the main reason for the recent recovery in the tree growth at middle and low elevations. Moreover, the increasing temperature significantly promoted tree growth at 3300 m, with a correlation coefficient between the temperature and BAI of 0.77 (p < 0.01). Our results implied that climate change drove different growth patterns at different elevations, which sheds light into forest management under the estimated future climate warming: those trees in low and middle elevations should be paid more attention with respect to maintaining tree growth, while high elevations could be a more suitable habitat for this species.

Modeling tree regeneration height growth after an experimental hurricane

2006 ◽  
Vol 36 (8) ◽  
pp. 2003-2014 ◽  
Author(s):  
Mary Ann Fajvan ◽  
Audrey Barker Plotkin ◽  
David R Foster
Keyword(s):  
Growth Rates ◽  
Height Growth ◽  
Growth Patterns ◽  
Tree Regeneration ◽  
Tree Seedlings ◽  
Red Maple ◽  
Yellow Birch ◽  
White Ash ◽  
Advance Regeneration ◽  
Species Specific

Annual height growth rates for six species of tree seedlings were modeled during the first 10 years of cohort initiation following an experimental hurricane in central Massachusetts. Selected canopy trees in a second-growth, transition oak – northern hardwoods forest were pulled over with a winch in a 50 m × 160 m area. Regeneration height growth did not follow the species-specific patterns anticipated if the disturbance had been stand replacing. Instead, the temporal increase in shade from crown expansion and sprouting of residual trees slowed cohort development and resulted in a variety of annual height growth patterns among species. Height development was followed separately for advance regeneration and new seedlings of red maple white ash, black cherry, black and yellow birch, paper birch, and red oak. All species had increasing height growth rates for 3 years followed by either decreasing or unchanged (flat) rates except red maple and ash advance regeneration, which had increasing rates throughout the measurement period. After 10 years, black and yellow birch, and red maple are the most numerous species and compose the majority of the tallest regeneration. Red oaks, which dominated the original stand, are few and unlikely to emerge to the canopy of the new cohort.

scholarly journals Comparison of the Radial Growth Response of Picea crassifolia to Climate Change in Different Regions of the Central and Eastern Qilian Mountains

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1015
Author(s):  
Xuan Wu ◽  
Liang Jiao ◽  
Dashi Du ◽  
Changliang Qi ◽  
Ruhong Xue
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Central Region ◽  
Radial Growth ◽  
Growing Season ◽  
Qilian Mountains ◽  
Growth Patterns ◽  
Total Precipitation ◽  
Picea Crassifolia ◽  
The Qilian Mountains

It is important to explore the responses of radial tree growth in different regions to understand growth patterns and to enhance forest management and protection with climate change. We constructed tree ring width chronologies of Picea crassifolia from different regions of the Qilian Mountains of northwest China. We used Pearson correlation and moving correlation to analyze the main climate factors limiting radial growth of trees and the temporal stability of the growth–climate relationship, while spatial correlation is the result of further testing the first two terms in space. The conclusions were as follows: (1) Radial growth had different trends, showing an increasing followed by a decreasing trend in the central region, a continuously increasing trend in the eastern region, and a gradually decreasing trend in the isolated mountain. (2) Radial tree growth in the central region and isolated mountains was constrained by drought stress, and tree growth in the central region was significantly negatively correlated with growing season temperature. Isolated mountains showed a significant negative correlation with mean minimum of growing season and a significant positive correlation with total precipitation. (3) Temporal dynamic responses of radial growth in the central region to the temperatures and SPEI (the standardized precipitation evapotranspiration index) in the growing season were unstable, the isolated mountains to total precipitation was unstable, and that to SPEI was stable. The results of this study suggest that scientific management and maintenance plans of the forest ecosystem should be developed according to the response and growth patterns of the Qinghai spruce to climate change in different regions of the Qilian Mountains.

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