While Christmas trees represent generosity and giving, these days they could also be associated with materialism and consumerism. Perhaps somewhat in contrast, Bodhirukka, or tree of enlightenment, is a certain tree associated with the awakening of each of the 29 Buddhas named in the Buddhavamsa, the Chronicle of Buddhas.
The gallery of trees below shows best guesses at anything I could find about trees listed (but not linked to by Wikipedia) for some of Buddhas 1-21. They are captioned with the number of the Buddha, followed by tree name listed in Buddhavamsa, then by common and/or latin tree name for the guess and link to source(s). Also included are tree images for Buddhas 22-29 (as linked to by Wikipedia.)
What can trees teach and help with right now? Stillness? Resilience? Effortless nourishment? Standing in your power? Giving and receiving? Majesty? Flexibility? Firmness? Want of recognition? Growth? Decay? Renewal? Earth connection? Wisdom? Mystery? Beauty?
1-Rukkaththana–Ruk-Aththana 
2-Kaela–Alphitonia-ponderosa—Kauila 
3-Pulila–Ulmus pumila (Ulmus gobicus) 
4-Pippala–Ficus religiosa 
5-Salakalyana–salacia reticulata 
10-Ajjuna–Terminalia arjuna 
14-Nipa–Nypa fruticans 
15-Welu (sounds similar to Willow)–Crack Willow 
16-Kakudha–Haritaki (Kadukkai) Tree–Terminalia Chebula 
17a-Champa–Ailanthus altissima 
17b-Champa–michelia-champaca 
18-Bimbajala–Neolamarckia cadamba—from search result (no explaination other than “religious significance”) 
21-Amalaka–Phyllanthus emblica — or amla from Sanskrit amalaki 
22 
23 
24 
25 
26 
27 
28 
29
Some other (legendary) trees:
Integrating Presence 