Betula- Birch Flashcards
Betula
Birch
Overview of Birch
Attractive trees and shrub-like trees
alternate simple leaves
narrow lenticels on bark
imperfect monoecious inflorescence
birches do not tolerate fall planting or excessive pruning well
prune in spring after leaves are fully expanded to minimize damage
Betula papyrifera
Paper birch
Paper birch- characteristics
native to sask (provincial tree); found in province close to water and in northern forests
medium sized tree with white bark
Paper birch- leaves
leaves coarsely serrate
often doubly serrate
ovate to narrow ovate
long petiole
accuminate leaf tip
acute to rounded at base
alternate attachment
Paper Birch- buds
green- brown can be pubescent
ovate acuminate
multiple overlapping scales
branches pubescent when young
Paper Birch- autumn colour
The reason they are grown ornamentally
Paper Birch- catkin
monoecious
male cone=like catkin formed in autumn
male catkin open in spring
female cone-like structures produced in spring
commonly shed in autumn but can shed over winter or next spring
Paper Birch- fruit
small 2 winged, heart shaped nutlets
1 seed/structure
quite small
Paper birch- attachment
on older growth, leaves are in 2’s or 3’s on short spurs
female catkins also produced on spurs
male catkins are produced at end of new grotwh
new growth alternate
Spurs
A short shoot bearing leaves or flowers and fruits
Paper Birch- bark
paper burch bark changes from dark brown (young)
than tan and than white as it ages
peels in wide strips
new bark underneath is white
dark horizontal lenticels common
Lenticel
gas exchange from outer atmosphere to the inner tissue
Paper birch- growth
basal growth very common
often is an indication there is dead top-growth
happens if you don’t prune correctly- indicator that tree is under stress
Betula pendula
European Weeping Birch
European Weeping birch- branches
branches are ascending but branchlets are pendulous
European Weeping birch- pest
Bronze birch borer- larvae stage eats phloem of the bark on the tree, can cause the top of the tree to die or even the whole tree
European Weeping Birch- diagnosing
exit holes
roughness to the bark; caused by insects burrowing under the bark, with sawdust pushing the dark out, giving it an uneven appearance
accumulation of sawdust
burrows made by insect in the phloem usually don’t burrow into the wood
can see channels if you rip off the bark
European Weeping birch- leaves
more coarse serration than paper birch
rhombic- ovate acuminate tip
often doubly serrate- going to be more aggressive in its serration
Cultivars of European Birch
Betula pendula ‘gracilis’ - Classic weeping birch
Betula pendula ‘laciniata’- Cutleaf weeping birch
Cutleaf weeping birch
was a very common tree in Saskatoon but many have died due to insects.
most popular for ornamentals
bordering along a maple leaf
very susceptible to bronze birch borer
Betula pendula ‘youngii’
Young’s weeping birch
used in highly intensive landscape like botanical gardens
often grafted onto a paper brich trunk at 1-2 m height.
Betula pendula ‘Purple Rain’
widely used as an ornamental because of the colour of the foliage
Betula fontinalis
Water/red/river birch
