TILE DRAIN

A buried perforated pipe designed to remove excess water from soils.

TILL

Predominantly unsorted and unstratified drift, deposited directly by and underneath a glacier without subsequent reworking by meltwater, and consisting of a heterogeneous mixture of clay, silt, sand, gravel, and boulders.

TILTING GATE

Hinged gate counterbalanced by weights that automatically opens and closes with a change in head.

TIMBER

Refers to trees only, excluding land, for the purpose of producing forest products.

TIMBER CRUISING

The process of estimating the quality, quantity, and characteristics of trees in a forest.

TIMBER STAND IMPROVEMENT (TSI)

Improving the quality of a forest stand by removing or deadening undesirable species to achieve desired stocking and species composition. TSI practices include applying herbicides, burning, girdling, or cutting.

TIMBER SUPPLY

Stumpage volumes that forest owners will harvest at different stumpage prices for a given region and year.

TIMBERLAND

Forestland producing, or capable of producing, crops of industrial wood (more than 20 cubic feet per acre per year), and not withdrawn from timber utilization. Formerly known as commercial forestland.