Evaluating the impact of competition using relative growth rate in red pine (Pinus resinosa Ait.) stands

A functional approach is proposed for comparing the development of individual red pine (Pinus resinosa Ait.) trees which had been growing under different intensities of competition from ages 13 to 43. Growth rate measures, based on absolute growth rate, relative growth rate and the ratio of absolute growth rate to crown width, were obtained from the differentiation of a cumulative growth function. Individual tree data were obtained from stands of the same age, but with different initial spacings: 1.5 × 1.5 m, 2.4 × 2.4 m, and 4.3 × 4.3 m. The Chapman-Richards function represented adequately the growth trends of individual trees. While cumulative growth indicated a fairly consistent pattern, that is, the bigger the tree initially, the bigger it remained, absolute growth rate was not related to tree size. Some of the smallest trees had the greatest absolute growth rate. Relative growth rate was more informative on the effect of competition. Before competition became severe, small trees had greater relative growth rates than large trees, and the effect of competition was to reverse this trend. The ratio of absolute growth rate to crown width indicated that the ability of trees to occupy the aerial growing space was not related to tree size. Key words: red pine (Pinus resinosa Ait.), growth functions, absolute growth rate, relative growth rate, functional approach

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Impact of Information and Communication Technologies on Research and Development: A Case of University of the Punjab-Pakistan

Pakistan Journal of Information Management and Libraries ◽

10.47657/201415760 ◽

2014 ◽

Vol 15 ◽

pp. 47-53 ◽

Cited By ~ 1

Author(s):

Nosheen Fatima Warriach ◽

Muzamil Tahira

Keyword(s):

Growth Rate ◽

Relative Growth Rate ◽

Information And Communication Technologies ◽

Research Productivity ◽

Doubling Time ◽

Research Output ◽

Communication Technologies ◽

Relative Growth ◽

Information And Communication ◽

The Impact

This study explores the research trends at Pakistani universities by highlighting the use of Information and Communication Technologies (ICTs) in the research process and its productivity. It also investigates the impact of Higher Education Commission (HEC) initiatives for research output in Pakistani universities in general and PU, in particular. It explores the essential ICT skills to increase research productivity as perceived by researchers from the Faculty of Social and Behavioral Sciences through structured interviews. An analysis of HEC of Pakistan and PU websites is carried out. The statistics of these websites shows that there is an increase in the number of research articles and PhDs produced every year. Data show that the respondents are not fully utilizing the pricey electronic sources provided by the HEC, yet there is a yearly increase in a number of PhDs produced and published research. The relative growth rate of research productivity and doubling time were not constant. It is also observed that doubling time has increased while the relative growth rate is going to decrease.

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Growth relationships in silver maple seedlings fumigated with O3 and SO2

Canadian Journal of Forest Research ◽

10.1139/x83-042 ◽

1983 ◽

Vol 13 (2) ◽

pp. 298-302 ◽

Cited By ~ 16

Author(s):

K. F. Jensen

Keyword(s):

Growth Rate ◽

Leaf Area ◽

Relative Growth Rate ◽

Growth Analysis ◽

Dry Weight ◽

Ozone Treatment ◽

Dry Matter Accumulation ◽

Relative Growth ◽

Silver Maple ◽

The Impact

Growth analysis was used to measure the impact of low levels of ozone, alone and with sulfur dioxide, on the growth of silver maple (Acersaccharinum L.) seedlings. The seedlings were fumigated for up to 60 consecutive days with cither 0.05, 0.1, or 0.2 ppm ozone, alone and with 0.1 ppm SO2 for 12 h per day. Dry weight and leaf area development curves were calculated from data collected at 10-day intervals throughout the study. Growth analysis variables were calculated from these curves. Three variables, relative growth rate, relative leaf area growth rate, and relative leaf weight growth rate, were reduced by 0.2 ppm ozone and decreased even further when 0.1 ppm SO2 was applied. Neither the 0.05 nor 0.1 ppm ozone treatment decreased the relative growth rate of the silver maple seedlings. Even small differences in growth rate may produce large differences in dry matter accumulation over a growing season.

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VARIACIÓN ESPACIO-TEMPORAL DE LA BIOMASA DEL ALGA CAULERPA SERTULARIOIDES EN POBLACIONES NATURALES Y EN CONDICIONES DE CULTIVO EN ESTANQUES DE CAMARÓN EN LA BAHÍA DE TUMACO, PACÍFICO COLOMBIANO

Bulletin of Marine and Coastal Research ◽

10.25268/bimc.invemar.2014.43.1.36 ◽

2016 ◽

Vol 43 (1) ◽

Author(s):

Hernel Marín Salgado ◽

Enrique Javier Peña Salamanca

Keyword(s):

Growth Rate ◽

Relative Growth Rate ◽

Algal Biomass ◽

Algal Species ◽

Natural Populations ◽

Ammonia Nitrogen ◽

Shrimp Ponds ◽

Relative Growth ◽

Culture Techniques ◽

The Impact

The biomass of natural populations and biomass under cultured conditions in shrimp ponds of the green alga Caulerpa sertularioides (Chlorophyta, Bryopsidales) was evaluated during March-December 2010 and January- June 2011. The algal biomass in the estuary was collected monthly at low tide using 625 cm2 quadrants. Water quality variables, such as dissolved oxygen, salinity, temperature, Secchi disk, NO3 -, NH3 and PO4 3-, were taken simultaneously with algal samples. Algal biomass was taken to the lab to remove debris. Afterward, wet and dry weights were obtained to get final biomass. Relative growth rate (RGR% d-1) in ponds as well as physicochemical variables was evaluated weekly. Growth rates of plants registered a mean of 1.69 % day-1 (± 0.97). There were no significant differences (p = 0.315) in terms of biomass of C. sertularioides between Natal and Pajal creeks, showing averages between 4.09 and 4.67 g cm-2. Algal biomass showed significant differences between seasons (p = 0.000039), with highest values recorded between July and September. Salinity in Natal creek showed a direct relationship with seasonal variation of algal biomass (p = 0.019), with highest values of biomass in July-September related to higher levels of salinity in the study area. In contrast, salinity values and algal biomass in Pajal creek did not show significant relationship (p = 0.97). Nitrates, ammonia nitrogen, and orthophosphate were not significant with respect to changes in algal biomass (p = 0.93; p = 0.33; p = 0.55, respectively). Significant differences (p = 0.0021) between biomass of natural populations and algal biomass in shrimp ponds were reported, with higher values in cultured conditions, being those three times the biomass of natural creeks. Values of algal biomass from natural creeks suggested the importance of perform culture techniques, since natural populations would not sustain a commercial exploitation of this species. This study reports the first data of growth of a potential algal species and it is necessary to develop additional experiments to assess the impact of additional environmental factors on the relative growth rate.

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