Sticker Stain in Hickory

Sticker stain is a warm-weather phenomenon. Here's advice about a suitable schedule for drying Hickory. May 27, 2014

I have kiln dried hickory in the past with no sticker stain problem. This was before the sap had come up in the wood. I run the NHLA schedule for 4/4 hickory (T8-D3). Has anyone had any problems with this in the past?

Forum Responses
(Commercial Kiln Drying Forum)
From Gene Wengert, forum technical advisor:
Sticker stain develops when the temperatures are warm. This just happens to also be when the sap in the tree is flowing. Actually, there is the same amount of sap in a tree year round. Sticker stain in hickory is a frequent problem. Check the archives for more info on this stain.

Also, I am interested in your statement about the NHLA kiln schedule. I am not aware that the NHLA has any kiln schedules. For hickory, however, T8 is very hot and is not suggested when color is an issue. Did you dry green from the saw or air-dry first?

From the original questioner:
All hickory had been started in the kilns green, with a MC of over 50% (some was as high as 70-75%). I have followed the guidelines set forth in the Agriculture Handbook No. 528 "Drying Eastern Hardwood Lumber". If this is not right, let me know so I can make changes.

From Gene Wengert, forum technical advisor:
I believe that if you check one of the appendicles in that book, you will find a schedule for hickory that will give whiter wood. Nevertheless, check the archives here for info on sticker stain. To avoid sticker stain, using a low initial RH is very important. I believe that T8-D3 uses 130 F (which is way too hot for white colors) and 84% RH start-up, which is way too humid.