TREX Glossary

acre-feet

is a unit of volume equal to the volume of a sheet of water one acre in area and one foot in depth; 43,560 cubic feet of water

age trend

a pattern of differing tree ring widths that result from early tree rings tending to be wider than later growth tree rings

boreal

of the north or northern regions

cross-dating

is a technique that ensures each individual tree ring is assigned its exact year of formation by matching patterns of wide and narrow rings between cores from the same tree, and between trees from different locations

dendrochronolgist

a scientist that focuses on dating events, environmental changes, and archaeological artifacts by using the characteristic patterns of annual growth rings in timber, tree trunks, and other wood samples

dendrochronology

is the science or technique of dating events, environmental change, and archaeological artifacts by using the characteristic patterns of annual growth rings in timber and tree trunks

detrending

the process of removing the non-climatic trends in the data to show only the absolute changes in tree-ring width and to allow potential cyclical patterns in tree rings to be identified

early wood

is the light colored portion of a tree ring produced in the spring

evapotranspiration

the process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants (moisture loss from stomatal pores on plants)

false ring

a layer of wood that appears to look like a complete ring, but is actually just a dark band that is not representative of the end of the growing season. The cellular structure is different than the ring of a complete ring.

late wood

is the darker part of an annual tree ring produced in the summer season

Law of Prior Appropriation

is the legal doctrine that the first person to take a quantity of water from a water source for "beneficial use"—agricultural, industrial or household —has the right to continue to use that quantity of water for that purpose

locally absent rings

are growth rings that are discontinuous around the stem so that it is absent at certain points; also referred to as a partial ring or missing ring

mega drought

is a prolonged drought lasting several years, to decades or longer

paleoclimate

a climate prevalent at a particular time in the geological past

paleoclimatologist

a science discipline that focuses on climatic conditions and their causes and effects in the geologic past using evidence found in glacial deposits, fossils, and sediments

Palmer Drought Severity Index

uses readily available temperature and precipitation data to estimate relative dryness. It is a standardized index that spans -10 (dry) to +10 (wet)

proxy data

is a past climate record like tree rings and ice cores used to interpret paleoclimate

skeleton plot

is a simple graphical representation of the ring width pattern in a sample tree ring core

talus

rock fragments that have accumulated at the base of a cliff or slope

wooly adelgids

small aphid-like insects that suck the sap from young twigs of hemlock, spruce, and fir trees. This prevents tree growth and causes needles to drop prematurely