Direct Human Causes
Timber Industry
Before the 1850s when settlers swarmed to the Coast of California during the gold rush, there were approximately 2 million acres of virgin , old growth Redwoods.
The redwoods started diminishing tremendously by the late 19th century when steam powered machinery was introduced and in the 20th century when gasoline powered machinery was introduced.
Redwood have excellent quality wood due to its high fire resistance and low rate of decay . As well as the fact that old growth trees have one of the largest volume of wood, ranging from 700-1000 cubic metres . Most of the old houses in California and Oregon were built from this because of its quality . As well as other developmental projects such as railroad sleepers and brdge timbers.
Urbanization
Also, about a quarter of the land that was once covered by old growth redwood forests have been converted to other uses like real estate developments and vineyards to meet the demand of expanding populations along the pacific coast which includes the coast along the Coastal redwood forests. Between 1980 and 2003 population has inceased by 46% int he pacific coast region.
Burl poachers
Currently, there have been increasing number of cases of ‘burl poachers’. Burl’s are unsprouted bud tissues that are found at the base of the tree and if removed, the tree is more vulnerable to external stressors such as diseases. The demand for burl is present in the black market due to its high quality and intricate patterns . These are then fashioned into objects such as furniture to be sold.
Due to the factors listed above, humans have directly affected the population of the Coastal Redwood forests as well as the health of the trees still standing
Fire Suppression
Frequency of forest fires has been on the decline since the European settlers came in. Reasonably there was an increase in fire suppression to protect their properties and health but this affects the forest dynamic. With more forest suppression, there would be an increase in forest density , underlying shrubs and closed canopies which only increases forests fuel .
An increase in forest fuel can potentially lead to more devastating and intense fires that perhaps even the old growth trees are not able to resist and may cause even larger impacts for settlements close by. It also affects the recycling of minerals on the soil which affects the germination of coast redwood seedlings.
*take note that national and state parks now do carry out fire management projects to prevent this from happening
check out: http://www.nps.gov/pore/learn/management/firemanagement.htm