What is an understorey?

What is an understorey?

The understory is the underlying layer of vegetation in a forest or wooded area, especially the trees and shrubs growing between the forest canopy and the forest floor. Plants in the understory comprise an assortment of seedlings and saplings of canopy trees together with specialist understory shrubs and herbs.

Which of the following has the greatest impact on fire spread and intensity?


What is Backdraft and why is it so dangerous?

A backdraft is a rapid or explosive burning of superheated gasses in a fire, caused when oxygen rapidly enters an oxygen-depleted environment; for example, when a window or door to an enclosed space is opened or broken. Backdrafts present a serious threat to firefighters.

What has the greatest influence on fire behavior?

Weather conditions such as wind, temperature, and humidity also contribute to fire behavior. Wind is one of the most important factors because it can bring a fresh supply of oxygen to the fire and push the fire toward a new fuel source.

What increases fuel moisture?

Fuels gain moisture during periods of high humidity and precipitation. Fuels lose moisture to the air when the air is dry and humidity is low. Moisture exchange between dead fuels and the air is affected by: differences in vapor pressure or the force of water vapor molecules in fuels and the air.

What are 10 hour fuels?

Ten-hour fuels are the smaller diameter dead fuels in the 0.

How does moisture affect the ability to start a fire?

Relative Humidity Moisture in the form of water vapor is always present in the atmosphere. And - the amount of moisture that is in the atmosphere affects the amount of moisture that is in the fuel. ... The lower the relative humidity, the more readily a fire will start and burn; the more vigorously a fire will burn.

What is critical live fuel moisture?

When the moisture content of living vegetation—also known as live fuel moisture—reaches a critical low threshold, fire danger becomes high. ... Hot and dry weather can lower live fuel moisture, but not all species respond the same way.

Can live fuels have a FMC fuel moisture content above 100 %?

In a word equation, it is: Percent Moisture Content = Weight of Water / Oven-dry Weight of Fuel x 100. Moisture content can be greater than 100 percent because the water in a fuel particle may weigh considerably more than the dry fuel itself.

What are the two types of horizontal arrangements of fuels?

What are the two types of horizontal arrangements of fuels?...

  • Torching.
  • Flare ups.
  • Crowning.
  • Increase in rate of spread.

What are three types of general winds?

There are three types of wind that are associated with wildland fire: general winds resulting from atmospheric activity, local winds resulting from unequal heating of land and sea surfaces, and winds resulting from a fire's buoyancy (also called entrainment).

What are the 4 types of wind?

The Earth contains five major wind zones: polar easterlies, westerlies, horse latitudes, trade winds, and the doldrums.

Is gravity a wind?

Gravity winds are winds that flow downhill under the pull of gravity. They occur mostly in mountainous or glacial regions where cold dense air from the mountain or glacier tops flows down the slopes under the influence of gravity. ... Gale force winds are frequently recorded near the coastal region.

How are winds named?

A wind is always named according to the direction from which it blows. For example, a wind blowing from west to east is a west wind. The ultimate cause of Earth's winds is solar energy. ... The greater the difference in pressure, the greater the force and the stronger the wind.

Why are there Santa Ana winds?

The combination of dry fuels, low humidity, and strong gusty winds create a critical fire weather threat. If a fire starts it can spread rapidly and behave erratically. Santa Ana winds occur in the fall lasting through the winter, so this is peak season and getting them now is normal.

Why is East Wind bad?

In Chapters 10 and 14 of Exodus, Moses summons the east wind to bring the locusts that plague Egypt and to part the Red Sea so that the Children of Israel can escape Pharaoh's armies. Several other references exist, most associating the east wind with destruction. Often, this is destruction of the wicked by God.