MR. THOMAS P. DONOHUE, D.C.
Chiropractic at 9 St, Ladysmith, WI

4901472, Feb 20, 1990

Sep 16, 1988

7/245891

Thomas P. Donohue - Ladysmith WI
Richard L. Nash - Ladysmith WI

H01G 1300

47 2

A frost protective device for citrus trees having a pad of thick, dark colored, water repellent urethane foam which may be wrapped in a cylinder around the budunion or branch of a citrus tree and secured in position using Velcro. RTM. or a similar fastener. Each protective device has a plurality of insulated pockets which receive individual exothermic heat sources such as dry-chemical warmers capable of producing high temperatures for a period of 1-3 days. To protect young trees from high initial temperatures and prolong the effective duration of the heat sources, other measures are utilized in combination with the protective device. One measure is controlling the exposure of the dry chemical packet to oxygen by varying the air flow properties of the insulating pocket or the air-tight wrapper initially enclosing the heat source, thereby regulating the resulting oxidation. Another measure consists of placing an insulating jacket of liquid-filled tubes between the heat sources and the tree, so that the liquid absorbs the excess initial heat and acts as a regulator and insulator for the transfer of subsequent heat to the tree, thereby preventing initial heat damage, conserving excess initial heat energy, absorbing and releasing that heat energy to prolong the effective usefulness of heat sources, and providing backup protection due to the potential heat of fusion of the liquid.