River Birch

River birch does not have white bark. UF/IFAS describes young bark as reddish-brown, peeling in papery curls. The Morton Arboretum calls it salmon-pink to cinnamon. The silvics manual says bark on an old trunk can turn dark reddish-brown to almost black, with thick irregular scales. Paper birch is the white one, and the two differ in more than colour.

The leaves are 1 to 4 inches, roughly diamond-shaped, with double teeth. Fall colour is a short-lived yellow.

River birch is a stream-bank tree. The silvics manual describes it as a pioneer on fresh alluvium, but says it tolerates flooding for no more than about three months of the growing season, which may explain why it is missing from much of the Mississippi flood plain. UF/IFAS says it tolerates low soil oxygen and clay but needs moisture and acid soil, and that it can grow 50 to 90 feet but is usually seen at 40 to 50. Open-grown 58-year-old trees in an Ohio study were 23 to 30 inches DBH and 50 to 65 feet tall, a fair guide to what an old yard tree can reach.

If the white bark is what the owner wanted, UF/IFAS names ‘Heritage’. Its beige, scaly bark is the closest thing to a paper birch that survives hot summers, and it is reported resistant to both bronze birch borer and leaf spot. UF/IFAS also argues for training river birch to a single trunk where structure matters, because nursery clumps of separate seedlings never fuse into one strong stem.

Bronze birch borer is a native beetle that goes after stressed birches. Three primary sources agree on river birch's standing. The Morton Arboretum lists Betula nigra as highly resistant and rarely affected. The silvics manual credits it with high resistance. UF/IFAS says it is less susceptible than other birches. The European white birch and Himalayan birch sit at the other end of Morton's list, as highly susceptible.

Morton calls birches bleeders and advises against spring pruning. NC State says not to prune in winter or spring while the sap is running. Wisconsin's extension service puts birch on its list of trees that bleed when cut in late winter and says the flow is unsightly but does not hurt the tree. For birches generally, the borer sets the window as well. Morton says to prune in fall, when adults are not active, because fresh cuts can attract them. Females lay eggs in late May or June.

Put together, that means cutting a birch from late summer into fall, and never in spring. The pruning calendar shows the birch row beside maple, the other famous bleeder, and the reasons are in when to prune trees.

UF/IFAS describes river birch as typically multi-trunked. It also notes that some nurseries plant two or three trees together to make a clump, and those trunks never fuse. That matters for measurement. The i-Tree Eco field manual takes DBH at 4.5 feet and records up to six stems on a forked tree, the largest ones. Stems joined below ground count as separate trees. Bark that runs all the way down between two stems to the soil line is a good sign that they are separate.

The combined figure is the square root of the sum of the squared diameters. It is the single stem with the same cross-section as the whole clump, and it is what the DBH calculator uses in multi-stem mode. Adding the diameters makes a mid-sized clump look like a heritage tree on a permit form. Check the threshold where you are with the permit checker.

River birch wants water. Morton lists it as drought-sensitive and recommends 3 to 4 inches of mulch and extra water in dry spells. NC State notes that it sheds interior leaves in summer droughts and drops a lot of twigs. UF/IFAS adds that it needs acid soil or it turns chlorotic, and that large trees are prone to trunk decay. Sound an old clump's stems before anyone climbs it.

A clump comes down as several smaller stems, not one big one, which usually means less rigging and more cuts. Price it in the removal cost calculator. The stump is as wide as the whole clump base, so measure that for the stump grinding calculator. For the wood, the BTU chart has a birch row at 20.8 million BTU per cord on the Utah State extension table, rated medium to split.