Question: How much sunlight do north-facing slopes receive compared to other slopes?
About the article "Grand Canyon", section "Plants".

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While most of the mountain ridges in New Jersey run generally north to south, Cushetunk Mountain primarily has an east-west ridge orientation because of the elongated north and south prongs of its horseshoe-like ridge.
This produces significantly different microclimates between the north facing and south facing slopes of the mountain.
On south facing slopes, the air temperature near the ground is consistently higher than on the north facing slopes, which do not receive as much sunlight.
In terms of ecology this creates a noticeable impact on Cushetunk Mountain’s vegetation.
Because the north slope of the mountain is cooler and shaded, moisture is more easily retained.
This results in larger trees, as well as the growth of trees not seen on southern facing slopes.
These trees include black birch, tulip tree, white ash, basswood, hickory, beech, and sugar maple.
Shrubs are abundant in the understory of the northern slopes, as well as herbs typical of more northern forests, including wild ginger, wild sarsaparilla, black snakeroot, and columbine.
On the warmer, dryer southern slopes chestnut oak and red oak prevail, although the trees are also common to the northern slopes.
In the understory, dogwood is dominant, and the diversity and number of shrubs is reduced.
Grasses and sedges are the most prevalent ground cover.
Wildlife supported by Cushetunk Mountain includes a variety of woodland birds, including a nesting pair of bald eagles.
Groundwater seeps, particularly on the northern slopes, provide habitat to amphibians, while outcrops of trap rock offer ideal environments for small reptiles. 
This species grows in arid regions at elevations from 1,100–2,000 meters (3,609–6,562 feet) on sunny, open, gentle rocky slopes or in small drainages in high desert scrub, grassland, and juniper and oak woodlands on gneiss substrate.
It grows on northern and eastern facing slopes where temperatures do not get very high compared to slopes with direct sunlight. 
Hillsides and slopes are preferred over flatter terrain: vines growing on a slope can receive a greater intensity of the sun's rays, with sunshine falling on an angle perpendicular to the hillside.
In flatter terrain, the intensity of the sunlight is diluted as it spreads out across a wider surface area.
Small slopes that are elevated above surrounding ground are the best and safest places for crops, because these small elevations are less prone to frost.
Additionally, a slope affords better drainage, obviating the possibility that the vine might sit in overly moist soil.
In cooler regions of the northern hemisphere, south-facing slopes receive more hours of sunlight and are preferred; in warmer climes, north-facing slopes are preferred.
In the southern hemisphere, these orientations are reversed. 
Japan uses a color-coded system, but shapes do not usually accompany them.
Some resorts, mainly those catering to foreigners, use the North American or European color-coding system, adding to the confusion.
When in doubt, check the map legend.
The usual ratings are:  Green: Beginner slopes.
These are usually near the base of the mountain, although some follow switchback routes down from the top.
Red: Intermediate slopes.
At most ski areas in Japan, these constitute the majority of the slopes (40% to 60%, depending on how the slopes are accounted).
Black: Expert slopes.
These are the steepest and most difficult slopes at the ski area.
The difficulty of these compared to like-classified slopes at other ski areas is heavily dependent on the target audience.
Japan has more than 1000 ski areas (115 in Nagano Prefecture alone), many of them small and family-oriented, so comparisons between slope classifications in Japan and "equivalent" slopes in Europe or North America are minimal. 
Aspect can have a strong influence on temperature.
This is because aspect affects the "angle" of the sun rays when they come in contact with the ground, and therefore affects the "concentration" of the sun's rays hitting the earth (amount of radiation divided by surface area, termed insolation).
The aspect of a slope can make very significant influences on its local climate (microclimate).
For example, because the sun's rays are in the west at the hottest time of day in the afternoon, in most cases a west-facing slope will be warmer than a sheltered east-facing slope (unless large-scale rainfall influences dictate otherwise).
This can have major effects on altitudinal and polar limits of tree growth and also on the distribution of vegetation that requires large quantities of moisture.
In Australia, for example, remnants of rainforest are almost always found on "east-facing slopes" which are protected from dry westerly wind.
Similarly, in the northern hemisphere a south-facing slope (more open to sunlight and warm winds) will therefore generally be warmer and dryer due to higher levels of evapotranspiration than a north-facing slope.
This can be seen in the Swiss Alps, where farming is much more extensive on south-facing than on north-facing slopes.
In the Himalayas, this effect can be seen to an extreme degree, with south-facing slopes being warm, wet and forested, and north-facing slopes cold, dry but much more heavily glaciated.
For a farmer, thus, choosing an aspect that will shelter from hot, dry winds or from cold can be critical to successful growth of crops.
Most farming agencies will state in manuals whether a crop prefers a pole ward or equator ward aspect (if this is important).
Glaciology is also influenced by aspect: unless precipitation patterns dictate otherwise (as in Iceland where glaciers accumulate on the much wetter south-western side) glaciers always accumulate downwards on the pole ward side of mountains.