Climate ChangeClick Here for a PDF of Climate Change
Potential impact of climate change on tree characteristics
Rain, temperature and other weather factors are being affected by shifts occurring in the climate. Tree characteristics and needs could change over time due to climate shifts. A discussion of potential climate changes, impacts and strategies to adapt to these impacts is provided in the 20-page PDF at this document link: Edible Trees and Climate, A Focus on Arizona.
Scientists cannot predict exactly how climate will change, but the changes listed below could occur in Arizona and the Southwest. These could affect where edible trees should be planted and how much water they will need.
Higher temperatures and lower rainfall could stress trees, such as this high water use pecan.
POTENTIAL CLIMATE CHANGES IN ARIZONA AND U.S. SOUTHWEST
Heat and drought changes
Higher average temperatures, increased droughts—including hotter drought periods and more wildfire due to heat and drought.
Decreases in precipitation of 5% to 10% compared to earlier values, especially in April, May and June—months that are already very dry. Possible more extreme variability in rainfall, with longer periods with no rainfall and more extreme rainfall events when rain does occur. More rain than snow compared to past ratios, but thicker deeper snowfalls when it is cold.
Higher evaporation rates. More water loss from soils. Possible decreased runoff to rivers and less recharge of groundwater.
Water demand changes
Increased outdoor water demand due to heat, drought and less rain. More competition for graywater between individuals and municipal systems. More competition for stormwater flows.
Water supply changes
Reduced surface water supplies flowing in the Colorado River, therefore lower flows to the CAP (Central Arizona Project canal) and reduced allocations to CAP water users. Possible rationing of municipal water supplies. Possible reduced groundwater recharge and higher groundwater pumping costs with deeper water levels. More rapid melting of mountain snowpack, shorter snowmelt period in the spring resulting in less runoff to landscapes and surface waters.
High winds during intense storms breaking limbs or uprooting trees; more dust storms.
Additional effects on edible trees
Stress due to lower rainfall and higher temperatures. Decreasing chill hours but not necessarily fewer freezing nights or less frost risk. Expanded range of insects that attack fruit trees. More competition for and reduced availability of conventional water supplies. Stress due to urban heat island effects in dense urban areas. Higher levels of the greenhouse gas CO2 potentially providing more “plant food.”
LEAF is under the fiduciary stewardship of the Arizona Community Tree Council, a 501(c)3 non-profit organization.
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