Forest carbon sink neutralized by pervasive growth-lifespan trade-offs.

Land vegetation is currently taking up large amounts of atmospheric CO2, possibly due to tree growth stimulation. Extant models predict that this growth stimulation will continue to cause a net carbon uptake this century. However, there are indications that increased growth rates may shorten trees' lifespan and thus recent increases in forest carbon stocks may be transient due to lagged increases in mortality. Here we show that growth-lifespan trade-offs are indeed near universal, occurring across almost all species and climates. This trade-off is directly linked to faster growth reducing tree lifespan, and not due to covariance with climate or environment. Thus, current tree growth stimulation will, inevitably, result in a lagged increase in canopy tree mortality, as is indeed widely observed, and eventually neutralise carbon gains due to growth stimulation. Results from a strongly data-based forest simulator confirm these expectations. Extant Earth system model projections of global forest carbon sink persistence are likely too optimistic, increasing the need to curb greenhouse gas emissions.

Phytophthora ramorum Colonizes Tanoak Xylem and Is Associated with Reduced Stem Water Transport.

ABSTRACT Isolation, detection with diagnostic polymerase chain reaction (PCR), and microscopy demonstrated the presence of Phytophthora ramorum in the sapwood of mature, naturally infected tanoak (Lithocarpus densiflorus) trees. The pathogen was strongly associated with discolored sapwood (P < 0.001), and was recovered or detected from 83% of discolored sapwood tissue samples. Hyphae were abundant in the xylem vessels, ray parenchyma, and fiber tracheids. Chlamydospores were observed in the vessels. Studies of log inoculation indicated that P. ramorum readily colonized sapwood from inoculum placed in the bark, cambium, or sapwood. After 8 weeks, radial spread of P. ramorum in sapwood averaged 3.0 to 3.3 cm and axial spread averaged 12.4 to 18.8 cm. A field study was conducted to determine if trees with infected xylem had reduced sap flux and reduced specific conductivity relative to noninfected control trees. Sap flux was monitored with heat-diffusion sensors and tissue samples near the sensors were subsequently tested for P. ramorum. Adjacent wood sections were excised and specific conductivity measured. Both midday sap flux and specific conductivity were significantly reduced in infected trees versus noninfected control trees. Vessel diameter distributions did not differ significantly among the two treatments, but tyloses were more abundant in infected than in noninfected trees. Implications for pathogenesis, symptomology, and epidemiology are discussed.

Discrepancies in parent and teacher ratings of adaptive behavior of children with multiple disabilities.

Parent and teacher ratings of adaptive skills of 59 children with multiple disabilities (mean age 6 years) in a rehabilitation day treatment setting were compared. The Vineland Adaptive Behavior Scales Classroom and Survey Editions were administered to each child's teacher and mother or other primary caretaker, respectively. Correlational analyses indicated a robust relation between Vineland forms; however, mean score comparisons indicated that teachers systematically rated the children as more skilled in both the global and the specific domains of adaptive behavior than did caretakers. Sources of interrater disagreement and implications for assessment of children with multiple disabilities were discussed.

Validity of self-report of adaptive behavior skills by adults with mental retardation.

The validity of self-reports of 48 adults with mental retardation of daily living competency using the recently revised Vineland Adaptive Behavior Scales (Sparrow, Balla, & Cicchetti, 1984) was investigated. Self-report was compared to standard Vineland interviews of subjects' program counselors and to demonstrated competency in a real-life setting. On domains measuring adaptive skills, the subject and counselor interviews yielded highly consistent results. On the optional Maladaptive Behavior domain, however, the subjects with mental retardation underreported problematic behavior. Response validity and implications for use of self-report for program planning and placement decisions were discussed.

Developmental trends in memory and metamemory in children with attention deficit disorder.

Examined the development of memory strategy knowledge and spontaneous use of strategy by 6- to 12-year-old boys with ADD-H. Metamemory knowledge of 12 ADD-H boys, unmedicated for study participation, and 12 matched control Ss was compared using a structured interview. Use of categorization was assessed using free recall of word lists differing in category composition (acoustic vs semantic categories) and list organization (clustered by category vs unclustered). Interview data indicated no difference between groups in development of metamemory knowledge. Analysis of free recall performance showed that ADD-H Ss were less likely than controls to benefit from that knowledge when strategy was less salient and involved effortful reorganization of stimuli (p less than .05). The results were consistent with a production deficiency. Developmental trends and implications for remediation are discussed.

Effects of chlordiazepoxide on novelty-induced hyperglycemia and on conditioned hyperglycemia.

Moving rats from their home cages to a different environment for a twenty minute period tended to raise plasma glucose levels (PGLs). In general, the more different the novel environment was from the housing condition, the greater the rise in PGL. Stimulus contexts that have led to conditioned hyperglycemia in previous experiments caused a larger rise in PGLs than stimulus contexts that led to conditioned hypoglycemia in previous experiments. These glycemic effects of environmental novelty did not habituate across seven exposure periods. Experiment 2 showed that chlordiazepoxide (CDP) reduced PGLs in animals transported to novel environments. Experiment 2 also showed that conditioned hyperglycemia occurred when insulin was administered in the environment that led to the highest PGLs in Experiment 1, and that conditioned hypoglycemia occurred in this same environment when the animals were regularly pretreated with CDP. Administering insulin in an environment that did not initially elicit a large rise in PGL resulted in a tendency towards conditioned hypoglycemia that was not influenced by CDP.

MMPI diagnosis of psychosis in epilepsy.

Clinical experience suggests that the diagnosis of psychosis in epilepsy with the MMPI is problematic, perhaps because the symptomatology of epilepsy and psychosis overlap. This study attempted to differentiate psychotic and nonpsychotic epileptics using the MMPI clinical and content scales, code-type categories, and modified Goldberg rule. A comparison group of schizophrenics was employed to explore differences between epileptic and schizophrenic psychoses. The failure of clinical scales and profile classification systems to differentiate the two epileptic groups implies that the MMPI might be insensitive to differential psychopathology in seizure-type subgroups.