Carbon sequestration potential and physicochemical properties differ between wildfire charcoals and slow-pyrolysis biochars

Pyrogenic carbon (PyC), produced naturally (wildfire charcoal) and anthropogenically (biochar), is extensively studied due to its importance in several disciplines, including global climate dynamics, agronomy and paleosciences. Charcoal and biochar are commonly used as analogues for each other to infer respective carbon sequestration potentials, production conditions, and environmental roles and fates. The direct comparability of corresponding natural and anthropogenic PyC, however, has never been tested. Here we compared key physicochemical properties (elemental composition, δ13C and PAHs signatures, chemical recalcitrance, density and porosity) and carbon sequestration potentials of PyC materials formed from two identical feedstocks (pine forest floor and wood) under wildfire charring- and slow-pyrolysis conditions. Wildfire charcoals were formed under higher maximum temperatures and oxygen availabilities, but much shorter heating durations than slow-pyrolysis biochars, resulting in differing physicochemical properties. These differences are particularly relevant regarding their respective roles as carbon sinks, as even the wildfire charcoals formed at the highest temperatures had lower carbon sequestration potentials than most slow-pyrolysis biochars. Our results challenge the common notion that natural charcoal and biochar are well suited as proxies for each other, and suggest that biochar’s environmental residence time may be underestimated when based on natural charcoal as a proxy, and vice versa

Grade 7 Learners' Performance in Five Macro Communication Skills in English

This study aimed to determine the performance of the grade 7 learners in five macro communication skills in English language learning at Cotabato City National High School- Main. Campus. Specifically, it determined their performance in listening focused on stress and intonation, speaking focused on correct production of vowel and consonant sounds and pitch levels, reading focused on comprehension and use of appropriate reading style, writing focused on writing purposes and sequencing sentences, and viewing focused on identifying meaning of signs and symbols and use of structural analysis. Finally, it determined the skills they performed best and worst. Thus, the subjects of this study were the 728 grade 7 students of CCNHS- Main Campus in the school year 2022-2023. Their performance in five macro communication skills were measured. The researcher used a quantitative descriptive design particularly teacher-made test in listening, speaking, reading, viewing and writing. The test questionnaire was based on the K-12 Curriculum Guide competencies which consisted of 50 test items for the five macro communication skills and divided it into 10 test items in each skill. Furthermore, after conducting the test, the results were analyzed and interpreted and came up with an output which is intervention materials in macro communication skills in English (listening, speaking, reading and writing). The intervention materials aims to help the grade 7 students in improving their communication skills namely listening, speaking, reading and writing. The findings revealed the following: the performance level of the grade 7 students in listening, speaking, and reading are all described as “did not meet expectations”; the grade 7 learners’ performance in viewing skill is found to be in the “very satisfactory” level; in writing skill, the grade 7 learners’ performance level is described as “fairly satisfactory”; their performance level in five macro communication skills is described as “fairly satisfactory”; and the learners perform best in viewing while they perform worst in reading. Based on the findings, it is concluded that the grade 7 learners are good viewers but they have very poor performance level in terms of listening, speaking, reading, and writing. The following recommendations are offered based on the findings and conclusion: the language teachers should utilize different strategies and activities to help improve students’ deficiency in listening, speaking, reading and writing; there is a need for students to involve actively in interactive activities in school or watch English tutorial videos in speaking and listening to enhance their listening and speaking skills, likewise, they may also engage in writing tasks to eventually overcome their deficiency in writing and they may expose themselves in different reading texts or books in order to improve their reading comprehension level; the school administrators should provide opportunities for the students to develop and to enhance their communication skills through different events conducted inside and outside the school such as seminar-workshops, trainings, and academic festivals or contests; the intervention materials constructed as an output should be used by the language teachers to remediate learners’ learning gaps; language teachers should integrate viewing English programs activity to enhance the students’ speaking skill; the Department of Education and school administrators should intensify monitoring the efficient implementation of reading programs under DepEd and see to it that all schools implement it, teachers need to implement the reading program religiously; and future researchers may conduct further study about the students’ English communication skills using different setting and respondents to validate the results of the study