Growth limitations of planted conifers regenerating under Montane Alternative Silviculture Systems (MASS): Seven-year results

2004 ◽  
Vol 80 (2) ◽  
pp. 241-250 ◽  
Author(s):  
A K Mitchell ◽  
B G Dunsworth ◽  
J T Arnott ◽  
R. Koppenaal ◽  
R. Benton ◽  
...  
Keyword(s):  
Treatment Time ◽  
Tsuga Heterophylla ◽  
Height Growth ◽  
Western Hemlock ◽  
Initial Growth ◽  
Vegetation Control ◽  
Abies Amabilis ◽  
Silvicultural System ◽  
The Impact ◽  
Effect On Growth

As part of the Montane Alternative Silviculture Systems (MASS) project, this study investigates limits on the growth of montane conifers resulting from varying overstory retention under conventional and alternative silvicultural systems. After harvesting treatments were complete in 1993, Abies amabilis (amabilis fir) and Tsuga heterophylla (western hemlock) seedlings were spring planted in replicated blocks of shelterwood (SW), patch cut (PC), green tree retention (GT) and clearcut (CC) systems. In addition, sub-plots were established within each silvicultural system in which fertilization (at planting) and vegetation control post-planting treatments were applied alone and in combination to test the extent to which growth limitations are related to nutrient availability and vegetative competition. The impact of overstory retention was most pronounced in the reduced light environment of the SW where height growth after seven years was 26-30% lower in both species compared to the untreated CC, GT and PC systems. Although the effect on growth of both species in the SW was mitigated somewhat by fertilization and vegetation control treatments, amabilis fir did not attain free-to-grow height (1.3 m) regardless of post-planting treatment. Time to free-to-grow height in the more open silvicultural systems was reduced in both fir and hemlock with fertilization and vegetation control alone and in combination, except in the CC where the initial growth response to fertilization alone was diminished by the end of the seven-year study. In contrast to fertilization, the effects of vegetation control on height growth were not apparent until three to five years and seven years after planting in the CC and GT, PC, SW, respectively. Combining vegetation control and fertilization had an additive effect on growth in amabilis fir but not in western hemlock. The effect of silvicultural systems and post-planting treatments on the two species illustrate that both above- and below-ground resource availability (light and nutrients) availability was potentially limiting to growth, particularly in the shelterwood treatment. Key words: MASS, silviculture systems, regeneration, Tsuga heterophylla, Abies amabilis, shelterwood, patch cut, green tree reten-tion, clearcut, fertilizer, vegetation control

STUDIES IN FOREST PATHOLOGY: VII. DECAY IN WESTERN HEMLOCK AND FIR IN THE FRANKLIN RIVER AREA, BRITISH COLUMBIA

1949 ◽  
Vol 27c (6) ◽  
pp. 312-331 ◽  
Author(s):  
D. C. Buckland ◽  
R. E. Foster ◽  
V. J. Nordin
Keyword(s):  
British Columbia ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Forest Pathology ◽  
Abies Amabilis ◽  
Armillaria Mellea ◽  
Forest Region ◽  
Volume Increment ◽  
Juan De Fuca

An investigation of decay in western hemlock (Tsuga heterophylla (Raf.) Sarg.) and fir (mainly Abies amabilis (Loud.) Forb.) in the Juan de Fuca forest region of British Columbia has shown that the major organisms causing root and butt rots are the same in both species. These are Poria subacida (Peck) Sacc., Fomes annosus (Fr.) Cke., Armillaria mellea Vahl ex Fr., Polyporus sulphureus Bull. ex Fr., and P. circinatus Fr. Those organisms causing trunk rots of western hemlock, in decreasing order of importance, are Fomes pinicola (Sw.) Cke., F. Pini (Thore) Lloyd, Stereum abietinum Pers., Fomes Hartigii (Allesch.) Sacc. and Trav., and Hydnum sp. (H. abietis). These same organisms causing trunk rots of fir, in decreasing order of importance, are Fomes pinicola, Stereum abietinum, Hydnum sp. (H. abietis), Fomes Pini, and Fomes Hartigii. The logs of 963 western hemlock were analyzed in detail. Maximum periodic volume increment was reached between 225 and 275 years of age. Maximum periodic volume increment was reached between 275 and 325 years of age in the 719 fir that were analyzed. Scars were the most frequent avenue of entrance for infection. In 59% of the cases of infection studied the fungus had entered through wounds.

Plant Water Stress and Soil Depletion in Variable-Density, Red Alder/Western Hemlock Coastal Oregon Plantations

2019 ◽  
Vol 66 (3) ◽  
pp. 304-313
Author(s):  
Elizabeth C Cole ◽  
Michael Newton
Keyword(s):  
Water Stress ◽  
Summer Precipitation ◽  
Growing Season ◽  
Variable Density ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Riparian Ecosystems ◽  
Replacement Series ◽  
Red Alder ◽  
The Impact

Abstract Riparian ecosystems provide critical habitat and functions while being some of the most productive areas in forests. Both conifers and hardwoods contribute to maintenance of habitat and function. To determine the impact of water stress on growth of red alder (Alnus rubra Bong.) and western hemlock (Tsuga heterophylla [Raf.] Sarg.), we installed Nelder type 1a combined with replacement series plots on three Oregon Coast Range sites. Densities ranged from 988 to 85,400 trees/hectare, with ratios (hemlock:alder) of 100:0, 75:25, 50:50, 25:75, and 0:100. In the first 4 years after planting, alder used water in the growing season at greater depths earlier than western hemlock. Higher densities resulted in greater water stress later in the growing season in weeded areas (maintained by herbicide applications), but stress was similar across densities in unweeded areas. Water stress at early ages was correlated with decreased size 14 or 24 years after planting for both species, but these correlations were confounded with other effects of density. Increasing water availability in areas with low summer precipitation could enhance growth of red alder and western hemlock, even in highly productive riparian areas.

Use of growth curve derivatives to illustrate acceleration and deceleration of growth in young plantations under variable competition

2006 ◽  
Vol 36 (10) ◽  
pp. 2515-2522 ◽  
Author(s):  
Michael Newton ◽  
Elizabeth C Cole
Keyword(s):  
Growth Period ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Early Years ◽  
Western Hemlock ◽  
Richards Equation ◽  
Second Derivative ◽  
Red Alder ◽  
Vegetation Control ◽  
Second Derivatives

Deceleration of growth rates can give an indication of competition and the need for thinning in early years but can be difficult to detect. We computed the first and second derivatives of the von Bertalanffy – Richards equation to assess impacts of density and vegetation control in young plantations in western Oregon. The first derivative describes the response in growth and the second derivative describes the change in growth over time. Three sets of density experiments were used: (i) pure Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), (ii) mixed Douglas-fir and grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), and (iii) mixed western hemlock (Tsuga heterophylla (Raf.) Sarg.) and red alder (Alnus rubra Bong.). Original planting densities ranged from 475 to 85 470 trees·ha–1 (4.6 m × 4.6 m to 0.34 m × 0.34 m spacing); western hemlock and red alder plots were weeded and unweeded. For the highest densities, the second derivative was rarely above zero for any of the time periods, indicating that the planting densities were too high for tree growth to enter an exponential phase. As expected, the lower the density, the greater and later the peak in growth for both the first and second derivatives. Weeding increased the growth peaks, and peaks were reached earlier in weeded than in unweeded plots. Calculations of this sort may help modelers identify when modifiers for competition and density are needed in growth equations. Specific applications help define onset of competition, precise determining of timing of peak growth, period of acceleration of growth, and interaction of spacing and age in determination of peaks of increment or acceleration or deceleration.

Above-ground biomass predicts growth limitation in amabilis fir and western hemlock seedlings

2003 ◽  
Vol 79 (2) ◽  
pp. 285-290 ◽  
Author(s):  
Alan K Mitchell ◽  
B Glen Dunsworth ◽  
Tom Bown ◽  
Jonathan A Moran
Keyword(s):  
Nitrogen Concentration ◽  
Volume Growth ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Stem Volume ◽  
Above Ground Biomass ◽  
Growth Limitation ◽  
Foliar Nitrogen ◽  
Abies Amabilis ◽  
Ground Biomass

Conifer regeneration on clearcut montane sites is frequently affected by post-planting growth stagnation. The ability to predict such stagnation would be a valuable asset to forest managers. In this study, we tested the usefulness of above-ground biomass and photosynthetic efficiency (as estimated by foliar nitrogen concentration) in diagnosing growth limitations in western hemlock (Tsuga heterophylla) and amabilis fir (Abies amabilis). Seedlings were grown under different silvicultural systems (clearcut, patch cut, green tree retention and shelterwood) and post-planting treatments (fertilization, vegetation removal) at the Montane Alternative Silvicultural Systems (MASS) site on Vancouver Island, BC. Foliar nitrogen was found to be a poor predictor of height and stem volume growth. However, above-ground biomass predicted current height and stem volume (year 3 after planting), as well as future stem volume (year 7 after planting), in both species. Above-ground biomass therefore represents a useful measure of likely future growth performance, and may provide early warning of incipient growth stagnation in these species. Key words: amabilis fir, Abies amabilis, biomass, western hemlock, Tsuga heterophylla, growth limitation, photosynthetic capacity, biomass, seedling growth, regeneration

scholarly journals Understory Tree Development with Repeated Stand Density Treatments in Coastal Douglas-Fir Forests of Oregon

2009 ◽  
Vol 24 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Jeffrey P.A. Shatford ◽  
John D. Bailey ◽  
John C. Tappeiner
Keyword(s):  
Stand Density ◽  
Tsuga Heterophylla ◽  
Height Growth ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Coast Range ◽  
Advanced Regeneration ◽  
Commercial Thinning ◽  
Sapling Growth ◽  
Stand Density Management

Abstract We studied the potential for stand density management treatments to increase growth rates of advanced regeneration in the understory of 50- to 70-year-old Douglas-fir (Pseudotsuga menziesii) forests. Study sites in Oregon included a mesic coastal site, a moderate coast range site, and a drier coast range foothills site. Commercial thinning treatments in 1974–1984 led to the establishment of Douglas-fir and western hemlock (Tsuga heterophylla) in the understory and, in 1997, parts of these same stands were thinned for a second time to release this advanced regeneration and promote two-story structure. Both species responded positively where overstory was reduced to 30–40 m2/ha, but western hemlock saplings grew 30–80% more rapidly than Douglas-fir. Average annual height growth of all western hemlock saplings that were more than 1.0 m tall in 1999 was 23–30 cm/year in twice-thinned stands but only 13 cm/year in denser, once-thinned stands. About one-half of all western hemlock saplings doubled or tripled their height in 4 years after a second overstory treatment; the largest 10% of these saplings grew 74–93 cm/year and now represents midstory structure. The response of Douglas-fir saplings to a partial overstory removal was limited. Repeated density management treatments in these Douglas-fir forests can accelerate growth of understory saplings, resulting in the development of two or more canopy layers over time; however, repeated and/or heavy thinning will be required for Douglas-fir sapling growth. Furthermore, because of western hemlock's potential for rapid height growth, some reduction of hemlock sapling density may be needed to maintain vigorous Douglas-fir.

Studies on periderm. II. Anthocyanidins in secondary periderm tissue of amabilis fir, grand fir, western hemlock, and western red cedar

1969 ◽  
Vol 47 (9) ◽  
pp. 1419-1422 ◽  
Author(s):  
D. B. Mullick
Keyword(s):  
Tsuga Heterophylla ◽  
Free State ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Abies Grandis ◽  
Abies Amabilis ◽  
Red Cedar ◽  
Western Red Cedar ◽  
Thuja Plicata Donn

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.

Prognostic value of absolute monocyte count in chronic lymphocytic leukaemia

2015 ◽  
Vol 156 (15) ◽  
pp. 592-597
Author(s):  
László Szerafin ◽  
János Jakó ◽  
Ferenc Riskó
Keyword(s):  
Chronic Lymphocytic Leukaemia ◽  
Prognostic Value ◽  
Lymphocytic Leukaemia ◽  
Treatment Time ◽  
Monocyte Count ◽  
Time To Treatment ◽  
Causes Of Mortality ◽  
The Absolute ◽  
The Impact ◽  
Overal Survival

Introduction: The low peripheral absolute lymphocyte and high monocyte count have been reported to correlate with poor clinical outcome in various lymphomas and other cancers. However, a few data known about the prognostic value of absolute monocyte count in chronic lymphocytic leukaemia. Aim: The aim of the authors was to investigate the impact of absolute monocyte count measured at the time of diagnosis in patients with chronic lymphocytic leukaemia on the time to treatment and overal survival. Method: Between January 1, 2005 and December 31, 2012, 223 patients with newly-diagnosed chronic lymphocytic leukaemia were included. The rate of patients needing treatment, time to treatment, overal survival and causes of mortality based on Rai stages, CD38, ZAP-70 positivity and absolute monocyte count were analyzed. Results: Therapy was necessary in 21.1%, 57.4%, 88.9%, 88.9% and 100% of patients in Rai stage 0, I, II, III an IV, respectively; in 61.9% and 60.8% of patients exhibiting CD38 and ZAP-70 positivity, respectively; and in 76.9%, 21.2% and 66.2% of patients if the absolute monocyte count was <0.25 G/l, between 0.25–0.75 G/l and >0.75 G/l, respectively. The median time to treatment and the median overal survival were 19.5, 65, and 35.5 months; and 41.5, 65, and 49.5 months according to the three groups of monocyte counts. The relative risk of beginning the therapy was 1.62 (p<0.01) in patients with absolute monocyte count <0.25 G/l or >0.75 G/l, as compared to those with 0.25–0.75 G/l, and the risk of overal survival was 2.41 (p<0.01) in patients with absolute monocyte count lower than 0.25 G/l as compared to those with higher than 0.25 G/l. The relative risks remained significant in Rai 0 patients, too. The leading causes of mortality were infections (41.7%) and the chronic lymphocytic leukaemia (58.3%) in patients with low monocyte count, while tumours (25.9–35.3%) and other events (48.1 and11.8%) occurred in patients with medium or high monocyte counts. Conclusions: Patients with low and high monocyte counts had a shorter time to treatment compared to patients who belonged to the intermediate monocyte count group. The low absolute monocyte count was associated with increased mortality caused by infectious complications and chronic lymphocytic leukaemia. The absolute monocyte count may give additional prognostic information in Rai stage 0, too. Orv. Hetil., 2015, 156(15), 592–597.

scholarly journals The Development of Patient Scheduling Groups for an Effective Appointment System

2016 ◽  
Vol 07 (01) ◽  
pp. 43-58 ◽  
Author(s):  
Yu Li Huang
Keyword(s):  
Access To Care ◽  
Treatment Time ◽  
Optimization Technique ◽  
Urgent Care ◽  
Patient Scheduling ◽  
Total Cost ◽  
Patient Type ◽  
Clinic Efficiency ◽  
The Cost ◽  
The Impact

SummaryPatient access to care and long wait times has been identified as major problems in outpatient delivery systems. These aspects impact medical staff productivity, service quality, clinic efficiency, and health-care cost.This study proposed to redesign existing patient types into scheduling groups so that the total cost of clinic flow and scheduling flexibility was minimized. The optimal scheduling group aimed to improve clinic efficiency and accessibility.The proposed approach used the simulation optimization technique and was demonstrated in a Primary Care physician clinic. Patient type included, emergency/urgent care (ER/UC), follow-up (FU), new patient (NP), office visit (OV), physical exam (PE), and well child care (WCC). One scheduling group was designed for this physician. The approach steps were to collect physician treatment time data for each patient type, form the possible scheduling groups, simulate daily clinic flow and patient appointment requests, calculate costs of clinic flow as well as appointment flexibility, and find the scheduling group that minimized the total cost.The cost of clinic flow was minimized at the scheduling group of four, an 8.3% reduction from the group of one. The four groups were: 1. WCC, 2. OV, 3. FU and ER/UC, and 4. PE and NP. The cost of flexibility was always minimized at the group of one. The total cost was minimized at the group of two. WCC was considered separate and the others were grouped together. The total cost reduction was 1.3% from the group of one.This study provided an alternative method of redesigning patient scheduling groups to address the impact on both clinic flow and appointment accessibility. Balance between them ensured the feasibility to the recognized issues of patient service and access to care. The robustness of the proposed method on the changes of clinic conditions was also discussed.

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