Stream I: Forestry

(a) Silvics. Silvics studies the life history, growth habits and site requirements of forest trees and stands in relation to their environment. Silviculture applies this knowledge to establish, tend and regenerate forests, so silvics is its scientific basis.

(b) Height to age. Site index is the average height of dominant and co-dominant trees at a reference (base) age, so it expresses the height-age relationship and measures site quality.

(c) Dominant. Dominant trees have crowns that rise above the general canopy and receive full light from above and from the sides. Co-dominant trees get light only from above, and suppressed trees get almost none.

(c) Selective cutting. Individual mature or chosen trees are removed periodically, and the stand is never cleared. This gives better yields and natural regeneration under the remaining trees.

(d) Dendrology. Dendrology is the study of trees, covering their identification, classification and nomenclature by species.

(b) Direct sowing. Conifers such as Pinus do not coppice or produce root suckers, so they regenerate from seed, either naturally or by direct sowing or planting nursery seedlings.

(c) Beta diversity. Beta diversity is the change in species composition between habitats or regions. Alpha diversity is species diversity within one habitat, and gamma diversity is the total diversity of a whole landscape or region.

(a) Population. A population is a group of interbreeding individuals of the same species living in an area. Several populations of different species together form a community.

(c) Ecesis. Ecesis is the successful establishment of a species in a new area: germination, growth and reproduction there. It is a stage in ecological succession.

(d) Sal heartwood borer. Hoplocerambyx spinicornis is a cerambycid beetle whose larvae bore into the heartwood of living, weakened Sal (Shorea robusta) trees.

(b) Mechanical thinning. Trees are removed or kept according to a fixed spacing or pattern, such as every third tree or every alternate row, without regard to crown class.

(a) Form quotient. Form quotient is the ratio of the diameter at some point above breast height (for example half the tree height or the top of the first log) to the diameter at breast height. It describes stem taper.

(d) Financial. Financial rotation is the rotation that gives the highest return on capital, such as the maximum soil expectation value. It counts the time value of money (interest), unlike physical or silvicultural rotations.

(c) Normality. A normal forest has an ideal distribution of age classes, growing stock and increment. It is the model against which actual forests are compared in management.

(a) Orthodox seed. Many orthodox seeds have hard, impermeable coats. Heat from fire cracks the coat (scarification) and so promotes rapid germination. Recalcitrant and fleshy-fruit seeds are killed or damaged by fire.

(d) Pinus roxburghii. Fusarium solani causes wilt and dieback in broadleaved species such as Dalbergia sissoo, and also affects Acacia and Delonix. The conifer pine is the least sensitive of these.

(a) Towards. When a tree leans towards the observer, the angle to its top is larger, so the measured height is overestimated. When it leans away, height is underestimated. Observers should measure from a position at right angles to the lean.

(a) Centre of the log. For tender volume the log is treated as a cylinder, using the mid-girth (Huber formula): $V = \frac{g_m^2 L}{4\pi}$, with $g_m$ the girth at the centre and $L$ the length.

(b) Shorea robusta. In the Forest Resource Assessment Nepal (2015), Sal had the largest volume and air-dried biomass of any species at national level.

(d) Dioecious. Dioecious species bear male and female flowers on separate individuals, as in Taxus and Populus. Monoecious species bear both on the same plant.

(d) Multistory agroforestry system. A home garden combines trees, shrubs, crops and often livestock in several vertical layers on the same land around the homestead.

(d) Before MAI. CAI rises faster than MAI and peaks earlier. It then falls and cuts MAI at MAI maximum, because MAI rises while CAI is above it and falls when CAI is below it.

(a) Cedrus deodara. Deodar is a western Himalayan species found only in western Nepal. The other three species occur in eastern Nepal.

(b) Taxus baccata. Yew is a shade-tolerant (shade-demanding) species that regenerates under a canopy. Albizia lebbeck and Juglans regia are light demanders.

(d) All of the above. REDD+ adds three activities to reducing deforestation and degradation: conservation of forests, sustainable management of forests, and enhancement of forest carbon stocks.