I have decided to concentrate my study on examining the state and discoloration of the needles on Blue Spruce trees in my study location. The distinctive blue-green needles of blue spruce trees are what make them renowned evergreens, but recently, I’ve observed several surrounding trees showing symptoms of trouble.
I documented the state of Blue Spruce needles across three distinct locations, each representing a unique point along an environmental gradient:
Swimming pool fence lining: The immediate area once I get out from the back of my building that is surrounded by human activity, features limited green space and potential pollution sources like trash cans and frequent human traffic. Canadian geese frequent the grassy lawn beside the pool on the other side, and Blue Spruce trees line the borders, shedding needles onto the ground.
Suburban neighborhood: Moving away from the urban area in the near vicinity of my building, I found myself in a cozy suburban neighborhood with more extensive landscaping and greenery. Blue Spruce trees could be found more densely packed near a retirement home.
Distant Urban Forest: Venturing further along the gradient, I reached a densely packed area with lots of tree cover with blue spruces and other fauna and minimal human disturbance.
Reflecting on my observations, I’ve come to this one hypothesis to explain the observed patterns in Blue Spruce needle health along the environmental gradient. I propose that environmental stressors, such as pollution and habitat fragmentation, exert varying degrees of pressure on tree health across different locations.
Expanding on my theory, I predict that Blue Spruce trees in suburban and urban settings will be more likely than those in distant urban forests to display needle discoloration and poor health. In particular, I expect to see more noticeable shedding and discoloration of needles in regions nearer to human activity and possible sources of pollution. To test my hypothesis, I’ll utilize environmental stressors (categorical) such as proximity to human activity and pollution sources as potential explanatory variables. Blue Spruce needle discoloration severity (continuous, measured on a scale from 1 to 3) will serve as the response variable.
