What is the self-thinning rule?
The self-thinning rule states that w, the mean biomass per plant in a dense monospecific stand, is related to p, the number of plants in a unit area of that stand, by the power law relationship w = Kp−λ, where λ is approximately three-halves.
What is the self-thinning curve?
A self-thinning curve describes the relationship between density and biomass in a population that is limited by a resource. As density declines (due to mortality), the bio- mass of each individual tends to increase.
What is the law of constant final yield?
Abstract. The Law of Final Constant Yield states that when density is sufficiently high and resources become limited, the effects of competition will result in a constant biomass due to a proportional decrease in the size of the individuals.
What does self-thinning mean?
A progressive decline in the density of a population of growing plants. During the course of the self-thinning process, individuals become larger as the population density declines.
Why does self-thinning occur?
(A) Self-thinning is initiated after crowding occurs, resulting in decreasing plant density p(t) with time t. (B) A high initial planting density p0 is compensated for by poor growth conditions for each individual resulting in a small individual biomass w at harvest after an initial growth time period (B-3).
Why do plants self thin?
Publisher Summary. The self-thinning rule describes plant mortality because of competition in crowded even-aged stands. First, large plants suppress small plants. The result is a “hierarchy of dominance and suppression” in which the smaller plants are at an accumulating disadvantage and finally die.
What is interference in ecology?
Definition. (ecology) A form of competition wherein organisms directly vie for resources, such as by aggression. Supplement. In biology, competition refers to the rivalry between or among living things for territory, resources, goods, mates, etc.
What is self-thinning in forest?
The self-thinning rule describes plant mortality because of competition in crowded even-aged stands. The result is a “hierarchy of dominance and suppression” in which the smaller plants are at an accumulating disadvantage and finally die.
What is the difference between exploitation and interference?
Interference competition occurs directly between individuals, while exploitation competition and apparent competition occur indirectly between individuals (Holomuzki et. Exploitation competition occurs when individuals interact indirectly as they compete for common resources, like territory, prey or food.
Which is the best description of the self thinning rule?
Thinning is mortality imposed on crops; selfthinning was therefore the label applied to mortality imposed by the crop on itself. The rule is best understood with respect to a graph of log biomass (log B) per unit area vs log density (log N ) of survivors (Fig. l), called a B-N diagram by Westoby (1981).
How does Yoda’s rule relate to self thinning?
The −3/2 power rule of self-thinning (also called the −3/2 power rule or Yoda’s law) relates average plant biomass to density when density-dependent mortality occurs, such that populations decline in density as biomass increases. Let M̄ and n be the mean plant biomass and density (stems per unit area).
What is the slope of the self thinning line?
The line of slope – 1/2 is the self-thinning line. Arrows indicate the trajectories that stands follow at different biomass-density combinations. See text for further discussion. log W = log C – 3/2 log N (4) on a graph of log W vs log N.
How does ecological field theory lead to self thinning?
Here we use ecological field theory and statistical mechanics to show how the stochastic nature of ecological interactions among individuals, due to spatial field effects such as the availability of neighborhood resources at the microscopic level, leads to self-thinning at the macroscopic level.