• Rainfall occurs throughout the year or with one dry month.
• maximum rain is associated with the passage oef the thermal equator (sun directly overhead).
• there are 2,000-4,000 mm of rain/year.
• average temperature 25 degrees celsius.
• relative humidity 80%

• epiphytes
• lianas (woody vines)
• stranglers

1. trees
2. shrubs
3. herbs

1. climbers such as woody-lianas and herbaceious-vines
2. stranglers, which begin life dependent on another plant, and later become independent (example, figs)
3. Epiphytes: which grow on the stem of another plant. Some send roots down to groud, some climb up tree trunks to branches.

Heterotrophic plants such as _____ & _____. These include both fungi and higher plants.

saprophytes and parasites.

These include both fungi and higher plants

1. legumes, which are canopy trees
2. bamboos, which are large "woody" grasses
3. tree ferns

• Vines, lianas, and epiphytes are all common and all exploit a "climb or grow to light" strategy 

• The Bark is remarkably thin, smooth, light-colorerd, sometimes green, often covered with lichens

• The trunks may be fluted or flanged, and the roots are concentrated near the surface of the soil.
• buttresses: are commong and found in many plant families, especially in the Dipterocarpaceae, Leguminosae, Sterculiaceae, and Bombacaceae. 
• a buttress is a flat triangular plate, modified from lateral roots. There are 1-10 per tree and they are correlated with wet soils.
• in the temperate zone they are an indicator of a wetland. 

they're most common in low altitudes with high rainfall and are generally absent from the temperate zone except as noted above.

there are several theories as to why they are present, but the usual explanation is that they provide mechanical strength in wet soils

"Walking Palm"

• Tree can actually move using their roots. 

• New leaves red, anthocyanin pigments, or are white or light green. All become greener as they mature.
• Nodding foliage is also common. That is, the new leaves are limp and hang downward. 

• many wet forest leaves have a drip-tip. For example, in a Sri Lankan rain forest, 90% of 41 species (20 families) have a drip-tip.
• the drip-tip appears to be an advantage because it drains excess water from leaf. 

Pollination Related Traits: Cauliflory

define Cauliflory

the production of flowers and fruit directly from the bark along tree trunks or branches.

-this is widespread in the tropical wet forest.

• a striking cauliflorous shrub from tropical Africa. 
• It belongs to the Snapdragon Family (Scrophulariaceae)

1. open at night
2. large in size (1-3.5 inches)
3. pale or white in color
4. very fragrant but smell like fermenting fruit or other somewhat unpleasant odors
5. copious dilute nectar
6. sometimes hanging from a peduncle (penduliflory)

what are the other characterisitcs of moist forests include:

1. Fewer species with buttresses
2. branching begins at a lower level.
3. more light penetrates to ground level and there are more understory shrubs and herbaceous plants
4. leaves of the canopy are mesophylls, but leaves of lower levels are microphylls.

leaves with less surface area and a lower surface area to volume ratio. 

-more adapted for water stress since they have fewer stomata through which water vapor is lost. 

-leaves with more surface area for photosynthesis, more stomata per unit area, and a high surface area to volume ratio.

-they require less energy per unit surface area to produce

-they are also capable of high photosynthetic rates when water is abundant. 

• flowering during the dry season is a common phenomenon. Blazes of color on the bare branches of the trees are a spectacular sight during the dry season.
• Janzen (1967) has argued, as follows, that the dry season is ideal time for many species to flower.
• Drought adapted vegetation is dominated by bushy trees and fall shrubs, many with spines or thorns.
• slender-stemmed lianas and succulents are common, but there are few herbs or grasses.

• leaf surface area is reduced or leaves are completely absent. Spines and thorns are common and water is stored inside the stems. Photosynthetic metabolism is altered to allow for carbon fixation to occur at night.
• members of the cactus family predominate in the American deserts

• California 
• Southern Europe
• Chile
• South Africa
• Coastal Australia

• Dense, low, scrub
• slopes and hills
• occur below 2,000 meters

There are many adaptations to fire:

1. Fire-induced flowering, bud production and sprouting
2. In-soil seed storage
3. Fire-stimulated germination and dispersal.

Chaparral recovers from fire in about 10 years.

• since fires burn very (600-700 degrees celsius) the soils of the chaparral tend to be hydrophobic.
• waxy resin residue from burned plants forms impermeable layer just below ground surface.
• water runs off, causes flooding
• area can see torrential rains (26 inches in 24 hrs in 1943)
• steep unstable slopes cause mud and landslides
• intense "debris flows"

• a cold winter alternates with a warm summer in which rainfall is limited (250-800 mm)
• characteristically the majority of the rainfall occurs in the spring; the summer can be very hot and dry.
• grasses, sedges and other herbs with an occasional tree dominate the vegetation.
• usually less than 10% tree cover
• also called Prairies (North America), Veldt (Southern Africa), Pampas (South America), and Steppes (Russia, Asia).

• A moist warm season alternates with a cold season where freezing temperatures are common.
• The climax vegetation is a forest dominated by angiosperms, which drop their leaves during the winter.
• this is the biome of the Fairfax County

• the distribution in a broad circumpolar band
• North America-Alaska to Newfoundland
• Eurasia-Scandinavia to northern Japan

• Northern limit: is the summer position of the arctic front
• Southern limit: winter position of the arctic front (just north of the 58 degrees N latitude)

• long, severe winters and short summers
• widge range of year-round temperatures.
• long summer of daylight hours
• limited precipitation, less than 300 mm of precipitation per year. 

• Podzols
• slow decomposition
• limited nutrient cycling. 

• high intensity
• more likely to be crown fires
• high tree mortality
• large burn area. 

• tundra encircles the top of the northern hemisphere and is a frozen plain, dominated by sedges, willows, and lichens, which grow on the rocks.
• low temperatures, a very short growing season and low precipitation characterize the climate
• vegetation is scant and scattered, interspersed with rocks and bare ground
• the soil is permanently frozen (Called permafrost)