black knot


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black knot

[¦blak ‚nät]
(plant pathology)
A fungus disease of certain fruit and nut trees that is characterized by black excrescences on the branches; destructive to plum, cherry, gooseberry, filbert, and hazel.
References in periodicals archive ?
Further, all white knots of the intermediate graph are replaced with black knots, with the index of variables of TN, which corresponds to discrete transformation of variables in time of TN, and the transmission functions of connections are replaced by their discrete transformations in time of TN.
Thus the proper black knots of the graph, being weakened signals of keys Ti, are united by single connections, i = 1, ..., N.
In yellow-birch, sound and black knots are not the most important defects, as one might find in softwoods.
Both systems were able to partially or correctly detect mineral streak, discoloration, sound knots, black knots, burl pocket, decay, blue stain, wane, split ([greater than or equal to] 0.3 mm), and through shake.
Figure 3 shows board #8 affected by coloration as well as sound and black knots. Discoloration, as found on board # 2, is used as an example to show the complexity of automated detection and the differences in detection capabilities of the four systems evaluated.
* Small black knots that are tight and not over 1/2" (12.7mm) in diameter or larger knots that are only partially black.
of knots, on the worst side and worst meter 1 piece 3 pieces Allowable knots (pieces/mm) Green knots 1 piece/10 mm 3 pieces/40 mm Red knots Not allowed 2 pieces/30 mm Decayed knots Not allowed Not allowed Black knots Not allowed Not allowed Cracks over 100 mm length Not allowed Max.
This grade will not permit black knots larger than 1/4 in.; open or missing knots; splits, checks or shake; wane, bark or pitch; stain or discoloration; pitch pockets over 1/8 in.
This grade will permit any size or number of round red knots (splits within the knot are acceptable and splits around the knot are acceptable up to two-thirds of the circumference of the knot); small black knots which are tight and not over 1/32 in.
This grade will permit any size or number of round red knots (splits within the knot are acceptable and splits around the knot are acceptable up to 2/3 of the circumference of the knot); small black knots which are tight and not over 1/32 in.