Bishop pine trees are very particular species found to grow in only a few locations in the world- Santa Cruz Island, Santa Rosa Island, and on one island off Baja California, as well as in some small areas in the cool and wet northern part of California.
A paper entitled “Cloud Shading and Fog Drip Influence the Metabolism of a Coastal Pine Ecosystem,” was published in the journal Global Change Biology, with a lead author Mariah Carbone, a postdoctoral fellow with UC Santa Barbara’s National Center for Ecological Analysis and Synthesis (NCEAS).
The paper explains how certain water inputs from clouds can have major influence on the carbon cycle and forest ecosystems. This is especially the case since clouds are the main cause of uncertainties in climate models. The study is of a high importance, since these interactions have not been studied extensively, particularly in Southern California.
Changes in temperatures affect the cloudiness, or cloud height, causing alterations in diversity of California forest ecosystems. As Carbone points out, changes in rainfall, together with higher sea-surface temperatures could affect fog density and low-stratus clouds.
This would have strong influence on the development of the Bishop pines on Santa Cruz Island, and the majestic coastal Redwood forests in Northern California, which have important carbon storage and removal functions. Moreover, these forests have invaluable aesthetic and recreation qualities.
These areas are characterized by extensive fogs from May to August, which form as a result of warm land and humid air over cold coastal waters. The air condenses and creates low clouds and fog banks under an atmospheric inversion layer. The study shows that this fog has strong influence on the state of the forests and hence the carbon cycle. According to A Park Williams, a co-author of the publication, this calls for a greater understanding of the way coastal summer conditions could transform under the influence of warmer climate. The former graduate student in UCSB’s Geography Department, now at Los Alamos National Laboratory explains that change in fogginess could create alterations in temperature, moisture and carbon feedback in coastal ecosystems, and cause similar problems as the ones expected from increased greenhouse gases.
For the study, the team used satellite data provided by NASA and NOAA to map the spatial distribution of cloud cover across the western part of Santa Cruz Island. The senior author Christopher J. Still, formerly an associate professor at UC Santa Barbara, now at Oregon State University, pointed out that the study was based on evidence of a cloud cover gradient from the coast to inland. The satellite data allowed quantification of this gradient and made the link between cloud cover and soil microbial activity possible. This is a novel approach, considering that previous research has mainly focused on plant-water relations.
The results indicate that frequency of fog drip influence soil microbial activity and metabolism in these ecosystems. The study also outlines two main effects of the clouds- shading and fog drips, and how they influence forest growth. This will help scientists understand the impact of climate change on forests and soils not only on this island, but also other islands located along the coast of California and Mexico.