Rates of non-suberized impervious tissue development after wounding at different times of the year in three conifer species

1976 ◽  
Vol 54 (9) ◽  
pp. 881-892 ◽  
Author(s):  
D. B. Mullick ◽  
G. D. Jensen

Rates of development of a non-suberized impervious tissue (NIT), which is a prerequisite to necrophylactic periderm formation, vary on the same tree with the changing environment at different times of the year. In Abies amabilis (Dougl.) Forbes, rates varied from 14 days in June, slowing gradually to 35 days in fall, virtually ceasing in winter, and resuming slowly (70 days) in spring. This cyclical pattern in rates of NIT formation was also found in Tsuga heterophylla (Raf.) Sarg. and Thuja plicata Donn. Fluctuations in the environment occasioned by year-to-year within-season variations appear to affect the physiology of NIT formation; in July, NIT developed after 21 days in 1968 and after 16 days in 1969, on the same A. amabilis. Preliminary observations indicate presence of intraspecific variations in the rates. Rates were consistently faster on the resistant than on the susceptible A. amabilis heavily infested with balsam woolly aphid, Adelges piceae Ratz. Possible causes of these variations and implications of the findings, in relation to process of NIT formation as a basic physiological host component in pathogenic interactions of bark, are discussed.


1975 ◽  
Vol 53 (21) ◽  
pp. 2443-2457 ◽  
Author(s):  
D. B. Mullick

Impermeability to OSO4 of periderm-free zones around the feeding sites of balsam woolly aphid (BWA), Adelges piceae, in the bark of Abies, was caused by a non-suberized impervious tissue (NIT). NIT developed at mechanical injuries in living bark of Abies grandis, Abies amabilis, Tsuga heterophylla, and Thuja plicata in 3 to 4 weeks during summer. It was found at healed injuries regardless of the cause, biotic or abiotic, at abscission scars, and at old resin blisters and rhytidome. It is concluded that NIT precedes formation of necrophylactic periderms (NP), may provide environment necessary for NP formation in tissues internally abutting NIT, and is a marker for distinguishing NP from exophylactic periderms. The imperviousness of NIT to water resulted neither from suberin (seven tests) nor from callose (three tests), and was detected by an F–F test, which is based on penetration of 2% FeCl3 followed by 4% K3Fe(CN)6 through the bark for 3 days each. The formation of NIT in the absence, e.g. rhytidome, as well as in the presence of injuries, BWA, and disease agents, suggests that NIT production is not only a non-specific inherent process but may be the physiological basis of host response to diseases in bark. Pathogen-free, "non-induced" NIT formation at rhytidome as a control process for isolating the host component of host–pathogen interactions is discussed.



2001 ◽  
Vol 79 (4) ◽  
pp. 389-397 ◽  
Author(s):  
Hugh J Barclay

Leaf angle distributions are important in assessing both the flexibility of a plant's response to differing daily and seasonal sun angles and also the variability in the proportion of total leaf area visible in remotely sensed images. Leaf angle distributions are presented for six conifer species, Abies grandis (Dougl. ex D. Don) Lindl., Thuja plicata Donn. ex D. Don, Tsuga heterophylla (Raf.) Sarg., Pseudotsuga menziesii (Mirb.) Franco, Picea sitchensis (Bong.) Carr. and Pinus contorta Dougl. ex Loud. var. latifolia. The leaf angles were calculated by measuring four foliar quantities, and then the distributions of leaf angles are cast in three forms: distributions of (i) the angle of the long axis of the leaf from the vertical for the range 0–180°; (ii) the angle of the long axis of the leaf for the range 0–90°; and (iii) the angle of the plane of the leaf for the range 0–90°. Each of these are fit to the ellipsoidal distribution to test the hypothesis that leaf angles in conifers are sufficiently random to fit the ellipsoidal distribution. The fit was generally better for planar angles and for longitudinal angles between 0° and 90° than for longitudinal angles between 0° and 180°. The fit was also better for Tsuga heterophylla, Pseudotsuga menziesii, Picea sitchensis, and Pinus contorta than for Abies grandis and Thuja plicata. This is probably because Abies and Thuja are more shade tolerant than the other species, and so the leaves in Abies and Thuja are preferentially oriented near the horizontal and are much less random than for the other species. Comparisons of distributions on individual twigs, whole branches, entire trees, and groups of trees were done to test the hypothesis that angle distributions will depend on scale, and these comparisons indicated that the apparent randomness and goodness-of-fit increased on passing to each larger unit (twigs up to groups of trees).Key words: conifer, leaf angles, ellipsoidal distribution.



2003 ◽  
Vol 33 (5) ◽  
pp. 854-861 ◽  
Author(s):  
Adrian Weber ◽  
Benjamin Gilbert ◽  
JP (Hamish) Kimmins ◽  
C E Prescott

Western redcedar (Thuja plicata Donn ex D. Don), a late successional species on northern Vancouver Island, has a low seedling survival in mature hemlock (Tsuga heterophylla (Raf.) Sarg.) – amabilis fir (Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes) (HA) stands. Shade, moss competition, and substrate were tested as causes of low cedar establishment. Cedar seeds were sown on reference and local soils isolated from surrounding soil, on nonisolated local soil, and on forest floor with moss removed. Western hemlock, amabilis fir, and cedar seeded on forest floor acted as controls. Treatments were implemented in the HA interior and the HA–clearcut edge, with soil treatments also implemented in clearcuts. Germinants and very young seedlings of cedar have a low leaf area of needle-like primary foliage. Cedar development of secondary foliage (the scale foliage normally associated with this species) was correlated with greater vigour and growth. Secondary foliage developed in the rankings forest edge and clearcut > forest interior, and reference isolated soil > local isolated soil > nonisolated local soil. Seedling survival rankings were edge > interior, and amabilis fir > hemlock > cedar on soil and with moss removed > cedar on forest floor. Cedar and amabilis fir showed a smaller growth response to light than hemlock. The results indicate that cedar, normally considered a late successional species, needs disturbance for early seedling establishment and survival and thus has some characteristics of an early seral species.



2000 ◽  
Vol 76 (2) ◽  
pp. 303-309 ◽  
Author(s):  
Christie Staudhammer ◽  
Valerie LeMay

Height equations for western hemlock (Tsuga heterophylla (Raf.) Sarg.), western red cedar (Thuja plicata Donn), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and alder (Alnus rubra Bong. and Alnus tenuifolia Nutt.) were fitted using dbh as the predictor variable. A simple, non-linear equation gave very similar results to the Weibull distribution, except for hemlock, which was better modelled using the more flexible Weibull distribution function. Introducing stand density variables into the base equations resulted in increased accuracy for predicting heights of alder. Smaller improvements were found for Douglas-fir, cedar, and hemlock. Key words: estimating height, Coastal BC, Weibull estimation, stand density measures



2004 ◽  
Vol 34 (8) ◽  
pp. 1730-1746 ◽  
Author(s):  
Taro Asada ◽  
Barry G Warner ◽  
Allen Banner

Sphagnum invasion 8 years after an experimental clear-cut and mounding field trial was examined in a mesic western redcedar (Thuja plicata Donn ex D. Don) – western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest on the outer north coast of British Columbia. Sphagnum invasion was prominent in wet hollows in the mounded blocks. Pioneer species, Sphagnum pacificum Flatb. and Sphagnum angustifolium (C. Jens. ex Russ.) C. Jens., were common despite being minor components in the precut forest. Sphagnum girgensohnii Russ., a species of forests, showed expanding colonies and contained some Sphagnum capillifolium (Ehrh.) Hedw. Comparisons of vertical growth and decomposition rates of Sphagnum in the experimental field site and in a nearby natural peatland suggest that peat accumulation potential in the Sphagnum colonies in the mounded blocks is similar to that in the natural peatland. These observations suggest that open peatland-type plant communities become established and paludification processes are beginning. Mounding may be an effective strategy for silvicultural management to improve tree growth in the short term but may initiate paludification and negatively impact forest productivity in the long term in hypermaritime lower productivity forests.



2002 ◽  
Vol 32 (11) ◽  
pp. 2043-2050 ◽  
Author(s):  
Douglas B Ransome ◽  
Thomas P Sullivan

Population dynamics of Glaucomys sabrinus (Shaw) and Tamiasciurus douglasii (Audubon and Bachman) were examined in commercially thinned and unthinned stands in British Columbia, Canada. We tested the hypothesis that commercial thinning would have negative short-term effects on the population dynamics of these species. Populations were monitored using mark–recapture techniques in two commercially thinned and two unthinned stands dominated by 60- to 70-year-old western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western redcedar (Thuja plicata Donn. ex D. Don). Populations were sampled intensively from August 1995 to May 1999 at Chehalis Lake and from May 1997 to March 2000 in the Malcolm Knapp Research Forest (MKRF). There were no differences among stands thinned and unthinned in movement, abundance, recruitment, survival, duration individuals remained in stands, percentage of males breeding, and mass of males for G. sabrinus or T. douglasii. Mean density of G. sabrinus in thinned and unthinned stands were 0.65 and 0.89 individuals/ha, respectively, at Chehalis and 0.09 and 0.51 individuals/ha, respectively, at MKRF. Mean density of T. douglasii in thinned and unthinned stands were 1.18 and 0.87 individuals/ha, respectively, at Chehalis and 1.08 and 1.00 individuals/ha, respectively, at MKRF. We concluded that commercial thinning had no negative short-term effects on the population dynamics of these species.



2018 ◽  
Vol 48 (9) ◽  
pp. 1073-1084 ◽  
Author(s):  
Kristina Kshatriya ◽  
Justin G.A. Whitehill ◽  
Lina Madilao ◽  
Hannah Henderson ◽  
Allison Kermode ◽  
...  

The seed coats of several conifers contain terpene-filled resin vesicles, which may be involved in the protection of the dormant embryo and the seed storage tissue against herbivores or pathogens. We analyzed the terpenoid composition of seeds from four Abies species (Abies amabilis Douglas ex J. Forbes, Abies balsamea (L.) Mill., Abies grandis (Douglas ex D. Don) Lindl., and Abies lasiocarpa (Hook.) Nutt.), two Thuja species (Thuja plicata Donn ex D. Don and Thuja occidentalis L.), and three Tsuga species (Tsuga canadensis (L.) Carrière, Tsuga mertensiana (Bong.) Carrière, and Tsuga heterophylla (Raf.) Sarg.) and examined histological features of resin vesicles in seeds from one species from each genus. Resin vesicle morphology was generally similar among the species analyzed. The composition of the seed terpenes varied largely between species. The described seed terpene profiles of the nine species will serve as a foundation for future studies into the function of seed terpenes and resin vesicles in the seed coat.



1973 ◽  
Vol 51 (8) ◽  
pp. 1459-1470 ◽  
Author(s):  
D. B. Mullick ◽  
G. D. Jensen

Field observations were made on wound and pathological periderms, regardless of the causal agent, and periderms formed at abscission zones, old resin blisters and rhytidomes in Abies amabilis (Dougl.) Forbes, Abies grandis (Dougl.) Lindl., Tsuga heterophylla (Raf.) Sarg., and Thuja plicata Donn. It was established that these periderms were of reddish-purple sequent periderm (rsp) type, rather than either the brown first periderm (bfp), or brown sequent periderm (bsp) types. These reddish-purple pigmented periderms, like the rsp (the usual sequent periderm) were found abutting necrotic tissues and were moreover identical with rsp in 15 newly demonstrated cryofixation and chemical characteristics. Because of this equivalence, it is proposed that all these reddish-purple periderms, including the usual sequent periderm (rsp), constitute one category, the necrophylactic periderms. These periderms arise whenever regeneration of a periderm after death of cells is required, and their main function seems to be protection of living tissues from the adverse effects associated with cell death. Because of the equivalence of bfp and bsp, they constitute another category, the exophylactic periderms. This second category of periderms has a common function of protecting living tissues against the external environment.



1969 ◽  
Vol 47 (9) ◽  
pp. 1419-1422 ◽  
Author(s):  
D. B. Mullick

By using a mild method, which precludes the possibility of pigment hydrolysis during extraction and processing, the occurrence of anthocyanidins in the free state has been detected in the normal secondary periderm tissues (rhytidomal region) of amabilis fir (Abies amabilis (Dougl.) Forbes), grand fir (Abies grandis (Dougl.) Lindl.), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western red cedar (Thuja plicata Donn.). Cyanidin was present in all species. Pelargonidin was present in western hemlock and most likely also in western red cedar.



1971 ◽  
Vol 49 (9) ◽  
pp. 1703-1711 ◽  
Author(s):  
D. B. Mullick

Field observations revealed distinctness of the first and sequent periderm pigmentation in each of 40 species from 13 genera of conifers. These distinctions in Abies amabilis (Dougl.) Forbes, Abies grandis (Dougl.) Lindl., Thuja plicata (Donn), and Tsuga heterophylla (Raf.) Sarg. were confirmed by a cryofixation and chemical techniques. The former technique depends upon fixation of tissues by freezing, and microscopic observation of cryostat sections in a frozen state, thus revealing the natural color of the pigments. The first periderm of the aforementioned four species is dark brown. It is replaced invariably by a reddish sequent periderm which always abuts the rhytidome. Additional reddish sequent periderms may continue to arise producing an ever-thickening rhytidomal zone. A second type of sequent periderm, dark brown in color, was found in three of the four species studied. This periderm, whenever present, was found abutting a reddish periderm and never abutting the rhytidome. The pigments are localized exclusively in phellem. The significance of the brownish sequent periderm in rhytidomal scaling and en masse sloughing, and its similarities to the first periderm are discussed.



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