The Basque/Euskara word burki
Word burki
Meaning birch

Comments
Possibly borrowed

Other words that might be of interest
gari ‘barley’, eRatz ‘broom, plant’, bi[h]i ‘grain’, berar ‘grass’, [h]oRi ‘leaf’, [h]aritz ‘oak’, oLo ‘oats’, irar ‘pea’, udare ‘pear’, le[h]er ‘pine’, golde ‘plough’, aLe ‘seed’, gali ‘wheat’, ardano ‘wine, fermented beverage’