Compare the practices of shelterwood cutting, clearcutting, and seed-tree cutting.

Ans.

Shelter-wood cutting is defined as a method of forest cutting that leads to establishment of a new seedling generation of a group a species or a particular species without planting. It is applied in those forests, which are considered as mature, generally after thinning.

Clear-cutting is a method of forest cutting, in which nearly all or most of the trees, found in an area are uniformly cut down. The principal objective behind clear-cutting is to regenerate a forest with healthier plants, instead of getting timbers.

Seed-tree cutting is defined as a method that uses removal of most of the trees from a region and leaving some trees behind, which can produce seed for the regeneration of that forest. It is used for the regeneration of tree that grow well in the presence of direct sunlight, such as pine trees.

the electromagnetic energy from the sun arrives in the form of visible and invisible light.

interphase

the period of cell growth when the cell synthesizes new molecules and organelles. the cell is not dividing and it constitutes the majority of the time spent in the cell cycle

prophase

changes occur in the nucleus and cytoplasm. the chromatin condenses to form structures (sister chromatids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact

prometaphase

the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids

metaphase

all the cell's duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle

anaphase

begins when sister chromatids separate from each other and ending when a complete set of daughter chromosomes arrives at each of the two poles of the cell

telophase

the daughter nuclei form at the two poles of a cell

cytokinesis

the division of a cytoplasm to form two separate daughter cells. usually occurs during telophase during mitosis. this and mitosis make up to mitotic (m) phase of the cell cycle