![]() ![]() Walnut (Juglans) has maple-like late winter sap flow Some tree species (see below), most notably the birches ( Betula), will exude sap from a spile in the later spring in response to positive root pressure. Most other species in the northern woods (including willow ( Salix), aspen ( Populus), elm ( Ulmus), ash ( Fraxinus), and oak ( Quercus)) do not exude sap and spend the winter with gas-filled vessels and water-filled adjacent fibers. The process occurs in all maples and sycamore (genera Acer and Platanus) and some other species, including butternut and walnut ( Juglans spp., Juglandaceae) that spend the winter with water-filled vessels with air-filled fiber cells adjacent to the vessels. In any given season, a maple producer may have the opportunity to collect sap on one or ten or more daily “runs” of sap. Tubes run from the vacuum device to the tapped sugar maples and carry sap to the collection location, Proctor research station, Underhill, VT.īecause it depends on weather (and water availability) instead of spring leaf flush, maple winter sap flow is intermittent and highly variable from year to year. When photosynthesis is done for the day, tension relaxes on the column of water in the xylem, and vessel pressure approximately equilibriates with that of soil water at the root surface. Transpiration during photosynthesis therefore pulls water up through the plant from the soil. Water moves up through the vessels to replace water lost through transpiration, in response to this pressure gradient. ![]() This water loss is called transpiration and creates tension, or negative pressure, in the water in the xylem. In doing so, however, the leaf must inevitably lose water by evaporation out of the stomata. In order to turn carbon dioxide into sugar through photosynthesis, the leaf must open its stomata (small pores on the leaf surface) so that carbon dioxide can diffuse into the leaf. Three primary processes can cause xylem sap to flow: transpiration, root pressure and stem pressure. Sap in the xylem moves passively, in response to physical forces, pressure and osmotic gradients. ![]() Linearilobum: Leaves are divided all the way to the base described as strap-, ribbon-, or bamboo-like.Tracheary elements sculptures, Kew Botanic Garden, UK.Dissectum: Leaves are deeply divided into lobes and sub-lobes described as lacy, dainty or ferny.Matsumurae: Leaves are divided more than 3/4 of the way to the base.Palmate: Leaves are divided 2/3 to 3/4 of the way to the base.Amoenum: Leaves are divided less than 2/3 of the way to the base. ![]() Below are common terms used to describe Japanese maple leaves. The leaves of Japanese maples can differ greatly between varieties, with some arranged in layers like roof shingles, some variegated along the margins or with webs of veining, and others that are curled, crinkled and clustered in tufts. Compact/dwarf: Growing to heights of just 3 to 6 feet, these types make an excellent choice for growing in a pot.Weeping: With pendulous branches that arch gracefully downward, weeping maples cascade in a similar fashion to a waterfall.Vase: The branches of these trees grow up and out, for a tree that is narrow at the base, but wide at the top.Here are the most common terms used to describe their forms. Japanese maples come in many forms-some are airy and upright, while others are compact and domed. Other often overlooked features are their sculptural trunks and branching, tufts of colorful flowers, and clusters of winged seeds called samaras. Some leaves are star shaped or nearly round some are deeply dissected and lacy. Some varieties are vase shaped, while others form columns or gracefully cascade. Small flowers bloom in mid-spring which are attractive close up, but not particularly showy from a distance. A small-growing, upright, rounded deciduous tree that also grows as a multi-stemmed shrub that is primarily grown for its excellent fall color. Photo by: Garden World Images Ltd / Alamy Stock Photo.Ĭommonly called full-moon maple or shirasawa maple, and similar in appearance to A. ![]()
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