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As stated by the General Ecology book, competition is the interaction between two species over a limiting resource that negatively affects one or both of their population growth rates. Intra specific competition is the competition between members of the same species. This can include competition for light, water, nutrients, and space. A tree's life traits are also of great importance. They can effect the distribution, abundance and density found in an area. Coniferous trees are those which keep their leaves throughout the winter.
They have small leaves called needles that are coated with wax to prevent water loss, and are soaked in resin which helps the needles withstand freezing. The needle shape is and asset in winter because it offers no resistance to wind. As a result of these adaptations conifers can grow where soils are shallow and poor, and where moisture is low. Another advantage of conifers is that they can hold their needles all winter and therefore, they can start photosynthesis early in spring as soon as the sun gets warmer and the ice melts. The coniferous tree used in this experiment was the white spruce. The white spruce tree grows in forests with well-drained soils.
Although the white spruce needs well-aerated water to grow efficiently it can survive in various moisture conditions and will grow on dry soil if it is fertile. The white spruce prefers sun but can also live in some shade. It is a hardy tree, withstanding wind, heat, cold, drought and crowding (Earl Rook 1998). This permits it to have a random distribution and high density. Since it can withstand such variety, abundance would be favorably strong. Deciduous trees are those that shed their needles in the fall and remain dormant in the winter so that they can survive until the spring.
Their leaves are wide and long which allows for maximum photosynthesis during their short growing season. This adaptation enables them to be better food producers than conifers. The deciduous tree used in this experiment was the poplar. Its canopy (highest level of foliage in a forest) typically allows more sunlight to reach the forest floor than do conifers. In addition to providing key habitat for wildlife, some may act as a nurse crop for shade-tolerant species that do not become established in full sunlight (eg. conifers) (Douglas Johnson 1999) The poplar is found in a variety of habitats, from dry or moist woods to the prairie parklands.
It grows best in well-drained moist soil. It will not tolerate shade, or soils that are saturated for a long period. Distribution is random, and there is a relatively high diversity of species, as well as regional variation according to local climate and substrate David T. Krone 2001).
We will investigate the intensity of intra specific competition on both the deciduous (poplar) and coniferous (white spruce) trees. Analysis will also be done on the different limiting resources that effect this competition. The hypothesis tested will be, that there is significant correlation between the distance of trees and the size. We are presuming that this hypothesis is correct. METHODS (Reference to Magdalena Park 2001) Field Procedure: 1) Got into groups of three and dispersed ourselves randomly throughout the study area, making sure to avoid dense / open sections. 2) We randomly selected ten tree pairs for sampling at each site. 3) We then measured and recorded (in centimeters) the distance between the first randomly selected live tree and its nearest live neighbour of the same species. The measurements were done from the centre of one tree to the centre of its neighbour.
Noting, that if a tree had two nearest neighbours to select the larger one. 4) Lastly, we measured and recorded (in centimeters) the circumference of the first tree and the circumference of its neighbour. Analysis: We did a correlation analysis. This is where the two variables of size and inter-distance are assumed to be related in some fashion, but each is subject to random variation. This analysis will assume that under a given set of conditions, variation in each of the variables follows a standard dispersal. The data will be Log transformed to achieve normality and to fit the assumption.
A two-tailed test was also done to determine the significance of the correlation coefficient. The calculated t value was compared to the critical t of 2. 306. Any value that exceeded this number was considered significant. The t-test value for the coniferous tree was 0. 4362, which indicates that it is not significant. The correlation coefficient for the coniferous tree was - 0. 15241; this could be related to the slight decrease in slope in figure 1. 1.
However, because there is not a substantial difference there is no correlation between the size and distance of trees. The t-test value for the deciduous tree was 0. 4603, which indicates that it is also not significant. The correlation coefficient for the deciduous tree was 0. 160615; this could be related to the slight increase in slope in figure 1. 2. Despite that, it is also not a substantial difference and therefore, the deciduous tree doesnt show a significant correlation between size and distance either. DISCUSSION The intensity of intra specific competition varied between the two tree types. I considered the three factors of seed dispersal, root systems and light requirement when looking at these differences.
Roots will grow wherever the environment is favorable. They require water, oxygen, minerals, support, and warmth. These requirements are usually found in the upper few feet of soil. Water and oxygen become unavailable when the pore spaces are closed (Sherry Rindels 1992). The white spruce is a gymnosperm, which means it produces seeds that are totally exposed. In the fertilization process immature male pollen grains are shed from the male cones in great numbers and are carried by wind to the female where and egg is produced and becomes a seed.
The seeds have wings that are dispersed by wind and travel primarily in the direction of prevailing winds. Most seed falls within about 300 feet of a source, but seeds have been found as far as 1, 300 feet (Earl J. S. Rook 1998).
Following dispersal, small mammals consume considerable amounts of seed off the ground. (Earl J. S. Rook 1998). Seeds remain viable for only 1 - 2 years. They grow best in full sunlight, but can tolerate low light, and can survive many years of shade. They produce more seeds than can be eaten by wildlife, allowing some seeds a chance to grow into trees.
There is a long time lapse between the appearance of cones and the maturation of seeds. Spruce trees are less light dependent than poplars because they have the ability to live in shade for long periods of time and still grow effectively. Spruce is shallow-rooted. Rooting depth is commonly between 36 and 48 inches, but taproots and sinker roots may descend to 10 feet (Earl J. S. Rook 1998).
The Poplar is an Angiosperm, which means it is a flowering plant that produces its seeds within a fruit. The seed is enclosed in a vessel or case. This provides more protection against animals and harsh conditions then the spruce seeds. Flowers play important roles in increasing the efficiency with which pollen is dispersed from plant to plant.
Pollen is wind dispersed, and seeds are embedded in a matrix of cotton-like fibers that provides flotation, enabling them to be carried long distances via wind and water (Steve Strauss 1997). Gymnosperms, which lack flowers, rely upon the wind to accomplish their pollen dispersal. On a per pollen grain basis, this may be a less efficient mechanism of dispersal. Poplar seeds are small and rapidly lose viability. They must find sites with abundant water and sunlight shortly after dispersal or they will not survive. Sexual reproduction is likely in this tree, but it mainly reproduces by vegetative means (asexual reproduction).
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Research essay sample on Differences Among Deciduous And Coniferous Trees
