In the catalog: Search under Tu bi-Shevat
On the shelf: most books will be in the BM 695 T9 section

In the catalog: search under Tu bi-Shevat--Liturgy or Tu bi-Shevat--Prayerbooks and devotions
On the shelf: most books will be in the BM 675 T8.2 section.

There are many examples available online as well, here are just a few:
JOFA Seder (at Ritualwell)
Rabbis for Human Rights
Shalom Center
Coalition on the Environment & Jewish life

Tu BiSh'vat at the Union for Reform Judaism
http://urj.org/holidays/tubishvat.shtml
Includes a short overview of the holiday with links to a parent resource page.

CAJE
http://www.caje.org/
The site discusses how the lessons of the holiday can be incorporated into lesson plans. There are many links and several PDF files available.

Tu Bishvat at www.MyJewishLearning.com
http://www.myjewishlearning.com/holidays/TuBishvat.htm
This site discusses the holiday from Rabbinic, Kabbalistic, Zionistist, and Ecological points of view.

While the Library thinks that these sites are useful, their content is not under our control and may express views that are not shared by the Hebrew Union College-Jewish Institute of Religion.

Search the catalog under Tu bi-Shevat--Study and teaching or check with the Tartak center (or email Tartak @huc.edu) for classroom materials

Environmentalism
Environmental protection
Trees (Jewish law) or Trees--Religious aspects--Judaism
Nature (and scroll down to Nature--Religious aspects)